fix(storage): address CI and review feedback

fix(storage): protect Yomitan profiles across Electron runtime changes
- Block unsupported or downgraded Electron runtimes before loading profile storage - Isolate development profiles and guard against unexpected dictionary loss
2026-08-22 00:15:26 -07:00 · 2026-08-18 22:42:26 -07:00 · 2026-08-18 22:19:47 -07:00
104 changed files with 1049 additions and 2175 deletions
@@ -274,8 +274,7 @@ jobs:
            config.example.jsonc \
            plugin/subminer \
            plugin/subminer.conf \
-            assets/themes/subminer.rasi \
-            assets/thumbnailers/subminer-ffmpegthumbnailer.thumbnailer
+            assets/themes/subminer.rasi

      - name: Generate checksums
        run: |
@@ -273,8 +273,7 @@ jobs:
            config.example.jsonc \
            plugin/subminer \
            plugin/subminer.conf \
-            assets/themes/subminer.rasi \
-            assets/thumbnailers/subminer-ffmpegthumbnailer.thumbnailer
+            assets/themes/subminer.rasi

      - name: Generate checksums
        run: |
@@ -2,10 +2,8 @@

 APP_NAME := subminer
 THEME_SOURCE := assets/themes/subminer.rasi
-THUMBNAILER_SOURCE := assets/thumbnailers/subminer-ffmpegthumbnailer.thumbnailer
 LAUNCHER_OUT := dist/launcher/$(APP_NAME)
 THEME_FILE := subminer.rasi
-THUMBNAILER_FILE := subminer-ffmpegthumbnailer.thumbnailer

 # Default install prefix for the wrapper script.
 PREFIX ?= $(HOME)/.local
@@ -223,13 +221,11 @@ docs-dev: ensure-bun


 install-linux: build-launcher
-	@printf '%s\n' "[INFO] Installing Linux wrapper/support artifacts"
+	@printf '%s\n' "[INFO] Installing Linux wrapper/theme artifacts"
 	@install -d "$(BINDIR)"
 	@install -m 0755 "$(LAUNCHER_OUT)" "$(BINDIR)/$(APP_NAME)"
 	@install -d "$(LINUX_DATA_DIR)/themes"
 	@install -m 0644 "./$(THEME_SOURCE)" "$(LINUX_DATA_DIR)/themes/$(THEME_FILE)"
-	@install -d "$(LINUX_DATA_DIR)/thumbnailers"
-	@install -m 0644 "./$(THUMBNAILER_SOURCE)" "$(LINUX_DATA_DIR)/thumbnailers/$(THUMBNAILER_FILE)"
 	@install -d "$(LINUX_DATA_DIR)/plugin/subminer"
 	@cp -R ./plugin/subminer/. "$(LINUX_DATA_DIR)/plugin/subminer/"
 	@if [ -n "$(APPIMAGE_SRC)" ]; then \
@@ -238,7 +234,7 @@ install-linux: build-launcher
 		printf '%s\n' "[WARN] No release/SubMiner-*.AppImage found; skipping AppImage install"; \
 		printf '%s\n' "       Build one with: make build"; \
 	fi
-	@printf '%s\n' "Installed to:" "  $(BINDIR)/subminer" "  $(LINUX_DATA_DIR)/themes/$(THEME_FILE)" "  $(LINUX_DATA_DIR)/thumbnailers/$(THUMBNAILER_FILE)"
+	@printf '%s\n' "Installed to:" "  $(BINDIR)/subminer" "  $(LINUX_DATA_DIR)/themes/$(THEME_FILE)"

 install-macos: build-launcher
 	@printf '%s\n' "[INFO] Installing macOS wrapper/theme/app artifacts"
@@ -279,9 +275,8 @@ uninstall:
 uninstall-linux:
 	@rm -f "$(BINDIR)/subminer" "$(BINDIR)/SubMiner.AppImage"
 	@rm -f "$(LINUX_DATA_DIR)/themes/$(THEME_FILE)"
-	@rm -f "$(LINUX_DATA_DIR)/thumbnailers/$(THUMBNAILER_FILE)"
 	@rm -rf "$(LINUX_DATA_DIR)/plugin/subminer"
-	@printf '%s\n' "Removed:" "  $(BINDIR)/subminer" "  $(BINDIR)/SubMiner.AppImage" "  $(LINUX_DATA_DIR)/themes/$(THEME_FILE)" "  $(LINUX_DATA_DIR)/thumbnailers/$(THUMBNAILER_FILE)" "  $(LINUX_DATA_DIR)/plugin/subminer"
+	@printf '%s\n' "Removed:" "  $(BINDIR)/subminer" "  $(BINDIR)/SubMiner.AppImage" "  $(LINUX_DATA_DIR)/themes/$(THEME_FILE)" "  $(LINUX_DATA_DIR)/plugin/subminer"

 uninstall-macos:
 	@rm -f "$(BINDIR)/subminer"
@@ -15,7 +15,7 @@ Integrates Yomitan and mpv - on-screen lookups, mine to Anki, and track immersio
 [![License](https://img.shields.io/github/license/ksyasuda/SubMiner?style=flat-square&color=1a1a2e)](https://www.gnu.org/licenses/gpl-3.0)
 [![TypeScript](https://img.shields.io/badge/TypeScript-1a1a2e?style=flat-square&logo=typescript&logoColor=3178c6)](https://www.typescriptlang.org)

-[![SubMiner demo](./assets/minecard.webp)](https://github.com/user-attachments/assets/7abab8a9-4e4e-4f06-9f3c-9783e15a3807)
+[![SubMiner demo](./assets/minecard.webp)](https://github.com/user-attachments/assets/89e61895-e2b7-4b47-8d50-a35afe4132b2)

 </div>

@@ -1,4 +0,0 @@
-[Thumbnailer Entry]
-TryExec=ffmpegthumbnailer
-Exec=ffmpegthumbnailer -i %i -o %o -s %s -f
-MimeType=video/matroska;video/matroska-3d;video/x-matroska;video/x-matroska-3d;
@@ -20,7 +20,7 @@
      "devDependencies": {
        "@types/node": "^24.10.0",
        "@types/ws": "^8.18.1",
-        "electron": "42.6.0",
+        "electron": "43.4.1",
        "electron-builder": "26.15.3",
        "esbuild": "^0.25.12",
        "eslint": "^10.8.0",
@@ -346,7 +346,7 @@

    "ejs": ["ejs@3.1.10", "", { "dependencies": { "jake": "^10.8.5" }, "bin": { "ejs": "bin/cli.js" } }, "sha512-UeJmFfOrAQS8OJWPZ4qtgHyWExa088/MtK5UEyoJGFH67cDEXkZSviOiKRCZ4Xij0zxI3JECgYs3oKx+AizQBA=="],

-    "electron": ["electron@42.6.0", "", { "dependencies": { "@electron-internal/extract-zip": "^1.0.1", "@electron/get": "^5.0.0", "@types/node": "^24.9.0" }, "bin": { "electron": "cli.js", "install-electron": "install.js" } }, "sha512-axGNgd+yCTg+vi1VEGrQqAj9WVWkePKwbICSAvMiT2eTaxhij9a/xhBHD6rXV8wrlW9ZfJzE5+xg752ImxrmTw=="],
+    "electron": ["electron@43.4.1", "", { "dependencies": { "@electron-internal/extract-zip": "^1.0.1", "@electron/get": "^5.0.0", "@types/node": "^24.9.0" }, "bin": { "electron": "cli.js", "install-electron": "install.js" } }, "sha512-5b+EuiwkgG5iRcsEL34rimgRpkYp15SsfZOa0pC5kXs0Tb82TH4n95rpQzTZa7yRCbA7tm0WoEbuBL6NaAhAcA=="],

    "electron-builder": ["electron-builder@26.15.3", "", { "dependencies": { "app-builder-lib": "26.15.3", "builder-util": "26.15.3", "builder-util-runtime": "9.7.0", "chalk": "^4.1.2", "ci-info": "^4.2.0", "dmg-builder": "26.15.3", "fs-extra": "^10.1.0", "lazy-val": "^1.0.5", "simple-update-notifier": "2.0.0", "yargs": "^17.6.2" }, "bin": { "electron-builder": "./cli.js", "install-app-deps": "./install-app-deps.js" } }, "sha512-a1KM5heqS3gQCZzizXEI8RjJy3QVogULPdeSknt76uLDpBIW/HDGsMg/XgP0riP6PI9COsRvFITKKGDqA8fJxA=="],

@@ -1,5 +0,0 @@
-type: fixed
-area: character dictionary
-
- Reuse character dictionaries after MeCab completes without finding any name splits instead of regenerating character data and portraits on every launch.
- Restore inline character portraits when a cached portrait index finishes loading after subtitles have already been tokenized.
@@ -0,0 +1,6 @@
+type: fixed
+area: dictionary
+
+- Upgraded the desktop runtime to Electron 43.4.1 and added profile guards that block unsupported runtimes and Electron downgrades before Yomitan storage is loaded.
+- Development launches now use a separate `SubMiner-dev` profile unless production-profile access is explicitly requested.
+- Automatic character-dictionary changes now stop when a previously non-empty Yomitan profile suddenly reports zero dictionaries.
@@ -1,4 +1,4 @@
 type: fixed
 area: subtitles

- Primary and secondary ASS subtitles now collapse layered and whitespace variants of full-span lyrics, including when playback starts or seeks into a line, reconstruct fragment-only karaoke per style, preserve authored stack order, keep canonical signs visible for their complete generated animation, navigate song lyrics by sanitized lines instead of generated animation events, and keep sidebar selections on the requested overlapping lyric while preserving unmatched dialogue and signs.
+- Primary ASS subtitles now use the active parsed cue when it fully accounts for mpv's live text, preventing fill, border, blur, and shadow copies of the same full-span lyric from appearing repeatedly while preserving unmatched overlapping dialogue and signs.
@@ -1,4 +1,4 @@
 type: fixed
 area: overlay

- Secondary subtitles now parse the selected ASS/SRT/VTT source with the primary subtitle deduplication pipeline, preventing layered animation text from appearing several times in the overlay, mined cards, and statistics. Long ASS lines repeated as dialogue and positioned signs are also collapsed when they differ only in whitespace or terminal punctuation. Dense multi-row sign layouts no longer become one concatenated secondary line. Live mpv text remains the fallback for unreadable tracks and applies full-line duplicate filtering before display.
+- Secondary subtitles now parse the selected ASS/SRT/VTT source with the primary subtitle deduplication pipeline, preventing layered animation text from appearing several times in the overlay, mined cards, and statistics. Live mpv text remains the fallback for unreadable tracks.
@@ -0,0 +1,4 @@
+type: docs
+area: documentation
+
+- Hid the unfinished feature demos page from the documentation sidebar while keeping its direct URL available.
@@ -1,4 +0,0 @@
-type: fixed
-area: launcher
-
- Fixed missing MKV thumbnails in the Linux rofi picker when system thumbnailer registrations only advertise legacy Matroska MIME aliases.
@@ -5,7 +5,7 @@ Short recordings of SubMiner's key features and integrations from real playback
 <script setup>
 import { withBase } from 'vitepress';

-const v = '20260819-1';
+const v = '20260301-1';
 </script>

 ## Anki Card Mining & Enrichment
@@ -64,6 +64,10 @@ make dev-watch                                # watch TS + renderer and launch E
 make dev-watch-macos                          # same as dev-watch, forcing --backend macos
 ```

+Development and debug launches use a separate `SubMiner-dev` profile so runtime experiments cannot modify the installed app's configuration or Yomitan dictionaries. To intentionally use the production profile for a development launch, set `SUBMINER_USE_PRODUCTION_PROFILE=1`. Use that override only after backing up the profile.
+
+Always launch source builds through `bun run dev` or `bun run electron`. SubMiner refuses to load its profile when the running Electron major differs from the version pinned by the repository.
+
 For mpv-plugin-driven testing without exporting `SUBMINER_BINARY_PATH` each run, set a one-time
 dev binary path with `mpv.subminerBinaryPath` in your SubMiner config. The launcher injects it into
 the mpv plugin at runtime:
@@ -88,7 +88,7 @@ features:
 <script setup>
 import { withBase } from 'vitepress';

-const demoAssetVersion = '20260819-1';
+const demoAssetVersion = '20260223-2';
 </script>

 <div class="landing-shell">
@@ -392,7 +392,7 @@ subminer -u
 subminer --update
 ```

-SubMiner verifies AppImage, launcher, and Linux support-asset downloads against `SHA256SUMS.txt`. On Linux those support assets include the launcher-managed runtime plugin copy under `SubMiner/plugin/subminer`, the rofi theme at `SubMiner/themes/subminer.rasi`, and the scoped Matroska thumbnailer registration under `SubMiner/thumbnailers`. If the binary is in a protected path, SubMiner shows the exact command to run rather than elevating itself.
+SubMiner verifies AppImage, launcher, and Linux support-asset downloads against `SHA256SUMS.txt`. On Linux those support assets include the launcher-managed runtime plugin copy under `SubMiner/plugin/subminer` plus the rofi theme at `SubMiner/themes/subminer.rasi`. If the binary is in a protected path, SubMiner shows the exact command to run rather than elevating itself.

 The tray "Check for Updates" entry installs the new app automatically on Linux, macOS, and Windows. On Linux it replaces the running `.AppImage` in place via `electron-updater` and refreshes the managed support assets from `subminer-assets.tar.gz`; AppImages managed by a system package (for example the AUR `/opt/SubMiner/SubMiner.AppImage`) are skipped so the package manager stays in charge.

@@ -404,7 +404,7 @@ SubMiner is an overlay that sits on top of mpv. It connects to mpv through an IP

 The `subminer` launcher handles mpv IPC socket setup automatically. If you launch mpv yourself or from another tool, you must pass `--input-ipc-server=/tmp/subminer-socket` (or `\\.\pipe\subminer-socket` on Windows) - without it the overlay starts but subtitles won't appear.

-The bundled mpv plugin is injected at runtime automatically - you don't need to install it separately. On Linux, the `subminer` launcher checks for its managed runtime plugin copy, rofi theme, and scoped thumbnailer registration before every mpv-managed launch and installs those support assets from the bundled app automatically if one is missing. For a rofi picker launch, this check runs before the picker opens. It provides in-player keybindings (the `y` chord) for controlling the overlay from within mpv. See [MPV Plugin](/mpv-plugin) for the full keybinding and configuration reference.
+The bundled mpv plugin is injected at runtime automatically - you don't need to install it separately. On Linux, the `subminer` launcher now checks for its managed runtime plugin copy and rofi theme before every mpv-managed launch and installs those support assets from the bundled app automatically if either one is missing. It provides in-player keybindings (the `y` chord) for controlling the overlay from within mpv. See [MPV Plugin](/mpv-plugin) for the full keybinding and configuration reference.

 ## Platform Notes

@@ -456,20 +456,18 @@ sudo chmod +x /usr/local/bin/subminer

 ### Linux Support Assets

-SubMiner ships the Linux rofi theme, scoped Matroska thumbnailer registration, and launcher-managed runtime plugin copy in `subminer-assets.tar.gz`:
+SubMiner ships the Linux rofi theme plus the launcher-managed runtime plugin copy in `subminer-assets.tar.gz`:

 ```bash
 wget https://github.com/ksyasuda/SubMiner/releases/latest/download/subminer-assets.tar.gz -O /tmp/subminer-assets.tar.gz
 tar -xzf /tmp/subminer-assets.tar.gz -C /tmp
 mkdir -p ~/.local/share/SubMiner/themes
 cp /tmp/assets/themes/subminer.rasi ~/.local/share/SubMiner/themes/subminer.rasi
-mkdir -p ~/.local/share/SubMiner/thumbnailers
-cp /tmp/assets/thumbnailers/subminer-ffmpegthumbnailer.thumbnailer ~/.local/share/SubMiner/thumbnailers/
 mkdir -p ~/.local/share/SubMiner/plugin
 cp -R /tmp/plugin/subminer ~/.local/share/SubMiner/plugin/subminer
 ```

-`subminer -u` and the tray updater keep those Linux support assets in sync automatically once the `SubMiner` data dir exists. Normal Linux launcher playback also auto-installs all three assets from the bundled app if one is missing, so manual extraction is mainly useful for pre-seeding or custom setups. Rofi receives the SubMiner data path through its process-local `XDG_DATA_DIRS`, so the thumbnailer registration does not change the desktop-wide configuration.
+`subminer -u` and the tray updater keep those Linux support assets in sync automatically once the `SubMiner` data dir exists. Normal Linux launcher playback also auto-installs the managed runtime plugin copy and rofi theme from the bundled app if either support asset is missing, so manual extraction is mainly useful for pre-seeding or custom setups.

 Override the theme path with `SUBMINER_ROFI_THEME=/absolute/path/to/theme.rasi`.

@@ -34,22 +34,18 @@ subminer -R -r -d ~/Anime              # rofi picker, recursive
 subminer -R /directory                 # rofi picker, directory shortcut
 ```

-rofi shows a GUI menu with icon thumbnails when available. SubMiner ships the rofi theme, a scoped `ffmpegthumbnailer` MIME registration, and the Linux launcher-managed runtime plugin copy in the release assets tarball:
+rofi shows a GUI menu with icon thumbnails when available. SubMiner ships the rofi theme plus the Linux launcher-managed runtime plugin copy in the release assets tarball:

 ```bash
 wget https://github.com/ksyasuda/SubMiner/releases/latest/download/subminer-assets.tar.gz -O /tmp/subminer-assets.tar.gz
 tar -xzf /tmp/subminer-assets.tar.gz -C /tmp
 mkdir -p ~/.local/share/SubMiner/themes
 cp /tmp/assets/themes/subminer.rasi ~/.local/share/SubMiner/themes/subminer.rasi
-mkdir -p ~/.local/share/SubMiner/thumbnailers
-cp /tmp/assets/thumbnailers/subminer-ffmpegthumbnailer.thumbnailer ~/.local/share/SubMiner/thumbnailers/
 mkdir -p ~/.local/share/SubMiner/plugin
 cp -R /tmp/plugin/subminer ~/.local/share/SubMiner/plugin/subminer
 ```

-Once the `SubMiner` data dir exists, `subminer -u` refreshes these assets automatically. Normal Linux launcher playback checks for all three assets and installs them from the bundled app when one is missing. For `subminer -R`, this repair runs before rofi opens.
-
-When `ffmpegthumbnailer` is installed, SubMiner prepends its own data directory to `XDG_DATA_DIRS` for the rofi process only. This lets rofi recognize the canonical Matroska MIME types used by newer GLib versions without changing the desktop-wide MIME or thumbnailer configuration. An existing registration in your own `$XDG_DATA_HOME/thumbnailers` still takes priority.
+Once the `SubMiner` data dir exists, `subminer -u` refreshes both assets automatically. Normal Linux launcher playback also checks for the managed runtime plugin copy and rofi theme before mpv launch and installs them from the bundled app automatically if either one is missing.

 The theme is auto-detected from these paths (first match wins):

@@ -110,8 +110,6 @@ The secondary bar is a compact top-strip region in the same overlay window. It s

 It is controlled by `secondarySub` configuration and shares its lifecycle with the main overlay window. Cycle which track feeds it with `Shift+J`.

-SubMiner collapses duplicate ASS layers in parsed secondary tracks. Long lines repeated as dialogue and positioned signs are treated as the same line when they differ only in whitespace or terminal punctuation. Dense multi-row sign layouts, such as translated timetables, are excluded instead of being concatenated into the secondary bar. When SubMiner must use mpv's live text as a fallback, it still filters full-line duplicates while preserving short repeated dialogue.
-
 ### Display Modes

 Both the primary and secondary subtitle bars share the same three visibility modes, and each can be changed independently at runtime:
@@ -9,7 +9,7 @@ The sidebar is enabled by default. Set `subtitleSidebar.enabled` to `false` if y
 When SubMiner parses the active subtitle source into a cue list, the sidebar becomes available. Toggle it with the `\` key (configurable via `subtitleSidebar.toggleKey`). While open:

 - The active cue is highlighted and kept in view as playback advances (when `autoScroll` is `true`).
- Clicking any cue seeks mpv into that line. For overlapping ASS karaoke, SubMiner moves past the previous line's exit animation when the selected cue has enough time remaining.
+- Clicking any cue seeks mpv to that timestamp.
 - The sidebar stays synchronized with the overlay - media transitions and subtitle source changes update both simultaneously.

 For typeset ASS karaoke and animated signs, SubMiner collapses generated animation frames and repeated full-line color phases before they reach the sidebar. It recovers a clean complete line from a matching timed authoring comment or from full-line events surrounding generated fragments. Ordinary ASS comments, editor notes, alternate lines, repeated dialogue, and separately positioned signs remain distinct.
@@ -109,6 +109,14 @@ If the overlay position is slightly off, right-click and drag on subtitle text t

 If you haven't set up dictionaries yet, see [Yomitan setup](/usage#yomitan-setup) first.

+**"Electron downgrade blocked" or "Unsupported Electron runtime"**
+
+SubMiner refuses to load Yomitan storage when the current Electron major does not match the app build, or when the profile was previously opened by a newer Electron version. Launch the packaged app or use the repository's `bun run dev` command. Do not delete the runtime safety record merely to force an older Electron version to open the profile.
+
+**"Yomitan reported zero dictionaries after previously reporting ..."**
+
+SubMiner detected that a previously non-empty Yomitan profile suddenly appears empty. Automatic character-dictionary changes are blocked so they cannot normalize or overwrite the suspicious state. Close SubMiner, preserve the profile directory, and restore a known-good backup before importing or deleting dictionaries.
+
 **"Yomitan extension not found in any search path"**

 SubMiner bundles Yomitan and searches for it in these locations (in order):
@@ -155,6 +155,7 @@ The tray menu also includes `View Changelog`, which opens the in-app changelog m

 - `--log-level` controls logger verbosity.
 - `--dev` and `--debug` are app/dev-mode switches; they are not log-level aliases.
+- `--dev` and `--debug` use a separate `SubMiner-dev` profile. They do not read or modify dictionaries and configuration from the installed app unless `SUBMINER_USE_PRODUCTION_PROFILE=1` is explicitly set.
 - `--background` starts at the default quieter logging level (`warn`), then follows `logging.level` after config loads. An explicit `--log-level` remains the override.
 - `--background` launched from a terminal detaches and returns the prompt; stop it with tray Quit or `SubMiner.AppImage --stop` (`SubMiner.exe --stop` on Windows).
 - Linux desktop launcher starts SubMiner with `--background` by default (via electron-builder `linux.executableArgs`).
@@ -3,7 +3,7 @@
 # Subtitle Overlay Priming

 Status: active
-Last verified: 2026-08-19
+Last verified: 2026-08-18
 Owner: Kyle Yasuda
 Read when: debugging subtitle state or blank Linux/X11 overlay windows when the visible overlay is shown or recreated

@@ -71,24 +71,11 @@ coming and prefetching would otherwise idle for the rest of the cue.

 - Primary live text first resolves recovered canonical ASS animations. Otherwise, when
  every live mpv line matches an active parsed cue, it uses the parsed cue text so exact
-  full-span style layers appear once instead of repeating for fill, border, blur, shadow,
-  or equivalent whitespace variants. Any unmatched live line keeps the complete live
-  stack, preserving dialogue or signs that overlap a lyric.
+  full-span style layers appear once instead of repeating for fill, border, blur, and
+  shadow events. Any unmatched live line keeps the complete live stack, preserving
+  dialogue or signs that overlap a lyric.
 - A tokenization cache miss emits the plain cue synchronously. Tokenization remains serialized so
  live work does not contend for Yomitan state.
- The initial `time-pos`, explicit renderer seeks, and later seek-like jumps reprocess mpv's
-  current raw `sub-text` after the new playback time is stored. Explicit intent matters because
-  adjacent subtitle jumps can be shorter than the general seek-distance threshold. This corrects
-  ASS cleanup when mpv delivered the destination subtitle before the destination timestamp.
- Renderer `sub-seek` commands use the active parsed cue list when available. Simultaneous cues
-  share one boundary, overlapping lyrics advance from the latest active boundary, and mpv's native
-  command remains the fallback when no parsed destination exists. This prevents generated karaoke
-  frames from consuming next/previous subtitle presses.
- Subtitle sidebar selections seek past the preceding sanitized cue's overlapping exit span when
-  the selected cue has enough time remaining. This keeps direct row selection on the requested
-  karaoke line while clamping the seek inside that cue.
- If startup paints raw text before embedded ASS parsing finishes, parsed cue arrival may replace
-  that provisional line. The one-prime-per-media guard still suppresses identical repeats.
 - If a newer cue arrives while an older line is still tokenizing, the newer plain cue or empty
  clear payload is emitted immediately. The older tokenization result is dropped before it can
  replace the current cue.
@@ -99,33 +86,15 @@ coming and prefetching would otherwise idle for the rest of the cue.

 - `secondary-sub-text` remains the immediate fallback, so unreadable and remote subtitle sources
  still appear without waiting for file resolution.
- Parsed secondary text and the live fallback share a flattened-line identity for long lines. This
-  removes dialogue/sign repetitions that differ only in whitespace or terminal punctuation while
-  retaining short repeated lines that can represent authored dialogue without source metadata.
 - `secondary-subtitle-track.ts` resolves `secondary-sid` against mpv's track list. External tracks
  are read directly; supported embedded text tracks are extracted through the same ffmpeg-backed
  source resolver used by primary subtitle prefetching.
 - The selected source is parsed with `parseSubtitleCues()`, including metadata-aware ASS duplicate
  and animation collapse. Playback `time-pos` selects the active parsed cue after applying
  `secondary-sub-delay`.
- Fragment reconstruction marks positioned parts that span multiple vertical rows as a grid.
-  Secondary text omits those grids instead of flattening a translated table or schedule into one
-  synthetic line. Reconstructed single-line karaoke remains eligible for display.
 - The resolved text is stored in `mpvClient.currentSecondarySubText` before it is broadcast. The
  overlay, mining, timing tracker, and immersion statistics therefore consume the same secondary
  text when a readable source is available.
- Simultaneous parsed cues use whitespace-insensitive identity, so ASS layers that vary only
-  between ordinary, hard, or ideographic spaces appear once.
- Simultaneous ASS lines are flattened in top-to-bottom positioned order, falling back to their
-  authored source order when no usable position exists.
- Fragment-only ASS karaoke is reconstructed per style before publication. Explicit spaces
-  survive concatenation, while scripts that discarded their word boundaries remain compact
-  instead of gaining false spaces between syllables. Short runs qualify only when overlapping
-  positioned events also show changing overrides or repeated layer copies; an English or romaji
-  style name alone never turns ordinary dialogue into a lyric.
- Recovered canonical ASS text remains active for the generated animation envelope. For
-  reconstructed lyric styles, the longest-lived active line wins over brief entrance and exit
-  fragments from the same style.
 - Media and `secondary-sid` changes clear the previous parsed state before refreshing the source;
  track-list changes refresh without discarding an unchanged source. Observed
  `secondary-sub-delay` changes retime the active parsed cue without rereading the file. If loading,
@@ -23,7 +23,6 @@ import {
  type HistorySeriesEntry,
 } from '../history.js';
 import type { Args } from '../types.js';
-import { ensureLinuxRuntimePluginAvailable } from '../runtime-plugin-preflight.js';
 import type { LauncherCommandContext } from './context.js';

 export type HistorySessionAction = 'previous' | 'replay' | 'next' | 'browse' | 'quit';
@@ -334,13 +333,6 @@ export async function runHistoryCommand(
  const { args, scriptPath } = context;

  checkPickerDependencies(args);
-  if (args.useRofi) {
-    await ensureLinuxRuntimePluginAvailable({
-      appPath: context.appPath ?? undefined,
-      scriptPath,
-      logLevel: args.logLevel,
-    });
-  }
  const themePath = args.useRofi ? findRofiTheme(scriptPath) : null;

  const dbPath = resolveImmersionDbPath();
@@ -2,7 +2,6 @@ import { fail } from '../log.js';
 import { runAppCommandWithInherit } from '../mpv.js';
 import { commandExists } from '../util.js';
 import { runJellyfinPlayMenu } from '../jellyfin.js';
-import { ensureLinuxRuntimePluginAvailable } from '../runtime-plugin-preflight.js';
 import { shouldForwardLogLevel } from '../types.js';
 import type { LauncherCommandContext } from './context.js';

@@ -65,13 +64,6 @@ export async function runJellyfinCommand(context: LauncherCommandContext): Promi
    if (args.useRofi && !commandExists('rofi')) {
      fail('rofi not found. Install rofi or omit -R for fzf.');
    }
-    if (args.useRofi) {
-      await ensureLinuxRuntimePluginAvailable({
-        appPath,
-        scriptPath,
-        logLevel: args.logLevel,
-      });
-    }
    await runJellyfinPlayMenu(appPath, args, scriptPath, mpvSocketPath);
    return true;
  }
@@ -496,39 +496,3 @@ test('playback command ensures Linux runtime plugin before mpv launch', async ()

  assert.deepEqual(calls, ['plugin', 'startMpv']);
 });
-
-test('rofi playback repairs support assets before opening the picker', async () => {
-  const context = createContext();
-  context.args = {
-    ...context.args,
-    target: '',
-    targetKind: '',
-    useRofi: true,
-  };
-  const calls: string[] = [];
-
-  await runPlaybackCommandWithDeps(context, {
-    ensurePlaybackSetupReady: async () => {},
-    ensureRuntimePluginReady: async () => {
-      calls.push('assets');
-    },
-    chooseTarget: async () => {
-      calls.push('picker');
-      return { target: '/tmp/movie.mkv', kind: 'file' };
-    },
-    checkPickerDependencies: () => {},
-    checkDependencies: () => {},
-    registerCleanup: () => {},
-    startMpv: async () => {
-      calls.push('startMpv');
-    },
-    waitForUnixSocketReady: async () => true,
-    startOverlay: async () => {},
-    launchAppCommandDetached: () => {},
-    log: () => {},
-    cleanupPlaybackSession: async () => {},
-    getMpvProc: () => null,
-  });
-
-  assert.deepEqual(calls, ['assets', 'picker', 'startMpv']);
-});
@@ -157,7 +157,6 @@ export async function runPlaybackCommand(context: LauncherCommandContext): Promi
      });
    },
    chooseTarget,
-    checkPickerDependencies,
    checkDependencies,
    registerCleanup,
    startMpv,
@@ -178,7 +177,6 @@ type PlaybackCommandDeps = {
    args: Args,
    scriptPath: string,
  ) => Promise<{ target: string; kind: 'file' | 'url' } | null>;
-  checkPickerDependencies?: (args: Args) => void;
  checkDependencies: (args: Args) => void;
  registerCleanup: (context: LauncherCommandContext) => void;
  startMpv: typeof startMpv;
@@ -203,18 +201,7 @@ export async function runPlaybackCommandWithDeps(
  await deps.ensurePlaybackSetupReady(context);

  if (!args.target) {
-    (deps.checkPickerDependencies ?? checkPickerDependencies)(args);
-  }
-
-  let runtimeAssetsReady = false;
-  const ensureRuntimeAssetsReady = async (): Promise<void> => {
-    if (runtimeAssetsReady) return;
-    await deps.ensureRuntimePluginReady(context);
-    runtimeAssetsReady = true;
-  };
-
-  if (!args.target && args.useRofi) {
-    await ensureRuntimeAssetsReady();
+    checkPickerDependencies(args);
  }

  const targetChoice = await deps.chooseTarget(args, scriptPath);
@@ -279,7 +266,7 @@ export async function runPlaybackCommandWithDeps(
    );
  }

-  await ensureRuntimeAssetsReady();
+  await deps.ensureRuntimePluginReady(context);

  await deps.startMpv(
    selectedTarget.target,
@@ -36,11 +36,6 @@ test('runUpdateCommand updates directly on Linux without launching Electron', as
        launcher: { status: 'updated' },
        supportAssets: [
          { status: 'updated', component: 'theme', message: 'Installed theme.' },
-          {
-            status: 'updated',
-            component: 'thumbnailer',
-            message: 'Installed rofi thumbnailer.',
-          },
          { status: 'skipped', component: 'plugin', message: 'Plugin already up to date.' },
        ],
      };
@@ -57,7 +52,6 @@ test('runUpdateCommand updates directly on Linux without launching Electron', as
    'info:AppImage update: updated',
    'info:Launcher update: updated',
    'info:Support assets (theme) update: updated - Installed theme.',
-    'info:Support assets (thumbnailer) update: updated - Installed rofi thumbnailer.',
    'info:Support assets (plugin) update: skipped - Plugin already up to date.',
  ]);
 });
@@ -21,10 +21,7 @@ import {
  parseSha256Sums,
  type FetchLike,
 } from '../../src/main/runtime/update/release-assets.js';
-import {
-  updateSupportAssetsFromRelease,
-  type SupportAssetsUpdateResult,
-} from '../../src/main/runtime/update/support-assets.js';
+import { updateSupportAssetsFromRelease } from '../../src/main/runtime/update/support-assets.js';

 type UpdateCommandResponse = {
  ok: boolean;
@@ -39,14 +36,15 @@ type DirectReleaseUpdateRequest = {
  channel: UpdateChannel;
 };

-type DirectSupportAssetsUpdateResult = Omit<SupportAssetsUpdateResult, 'status'> & {
-  status: string;
-};
-
 type DirectReleaseUpdateResult = {
  appImage: { status: string; command?: string; message?: string };
  launcher: { status: string; command?: string; message?: string };
-  supportAssets: DirectSupportAssetsUpdateResult[];
+  supportAssets: Array<{
+    status: string;
+    component?: 'theme' | 'plugin';
+    command?: string;
+    message?: string;
+  }>;
 };

 type UpdateCommandDeps = {
@@ -131,7 +129,12 @@ function readUpdateChannel(root: Record<string, unknown> | null): UpdateChannel

 function logUpdateResult(
  label: string,
-  result: DirectSupportAssetsUpdateResult,
+  result: {
+    status: string;
+    component?: 'theme' | 'plugin';
+    command?: string;
+    message?: string;
+  },
  configuredLogLevel: NonNullable<LauncherCommandContext['args']['logLevel']>,
  deps: Pick<UpdateCommandDeps, 'log'>,
 ): void {
@@ -73,21 +73,20 @@ function makeTestEnv(homeDir: string, xdgConfigHome: string): NodeJS.ProcessEnv
  };
 }

-// On Linux the playback path runs `ensureLinuxRuntimePluginAvailable`, which
-// spawns the app with `--ensure-linux-runtime-plugin-assets` when managed
-// support assets are missing and polls up to 30s
+// On Linux the playback path runs `ensureLinuxRuntimePluginAvailable`, which —
+// when the runtime plugin/theme are missing — spawns the app with
+// `--ensure-linux-runtime-plugin-assets` and polls up to 30s
 // (RESPONSE_TIMEOUT_MS) for an install response. A fake app that just exits
 // never writes that response, so the launcher hangs and the test times out on
 // Linux CI (the preflight is a no-op on macOS/Windows). This shell prelude makes
-// the fake app install the managed support assets and write the response, matching
+// the fake app install the managed plugin/theme and write the response, matching
 // launcher/smoke.e2e.test.ts. Prepend it to each fake app that reaches playback.
 const RUNTIME_PLUGIN_PREFLIGHT_SH = `if [ "$1" = "--ensure-linux-runtime-plugin-assets" ]; then
  data="\${XDG_DATA_HOME:-$HOME/.local/share}/SubMiner"
-  mkdir -p "$data/plugin/subminer" "$data/themes" "$data/thumbnailers"
+  mkdir -p "$data/plugin/subminer" "$data/themes"
  printf -- '-- test plugin\\n' > "$data/plugin/subminer/main.lua"
  printf 'test=true\\n' > "$data/plugin/subminer.conf"
  printf '/* test theme */\\n' > "$data/themes/subminer.rasi"
-  printf '[Thumbnailer Entry]\\n' > "$data/thumbnailers/subminer-ffmpegthumbnailer.thumbnailer"
  if [ "$2" = "--ensure-linux-runtime-plugin-assets-response-path" ] && [ -n "$3" ]; then
    mkdir -p "$(dirname "$3")"
    printf '{"ok":true,"status":"installed","path":"%s"}' "$data/plugin/subminer/main.lua" > "$3"
@@ -3,12 +3,7 @@ import assert from 'node:assert/strict';
 import fs from 'node:fs';
 import path from 'node:path';
 import os from 'node:os';
-import {
-  findRofiTheme,
-  findRofiThumbnailerDataRoot,
-  formatRofiPrompt,
-  prependXdgDataDir,
-} from './picker';
+import { findRofiTheme, formatRofiPrompt } from './picker';

 // ── formatRofiPrompt: spacing between prompt and input field ──────────────────

@@ -28,7 +23,6 @@ test('formatRofiPrompt leaves an empty prompt empty', () => {
 // ── findRofiTheme: Linux packaged path discovery ──────────────────────────────

 const ROFI_THEME_FILE = 'subminer.rasi';
-const ROFI_THUMBNAILER_FILE = 'subminer-ffmpegthumbnailer.thumbnailer';

 function makeFile(filePath: string): void {
  fs.mkdirSync(path.dirname(filePath), { recursive: true });
@@ -127,42 +121,3 @@ test('findRofiTheme resolves ~/.local/share/SubMiner/themes/subminer.rasi when X
    fs.rmSync(baseDir, { recursive: true, force: true });
  }
 });
-
-test('findRofiThumbnailerDataRoot resolves the managed XDG data root', () => {
-  const xdgDataHome = fs.mkdtempSync(path.join(os.tmpdir(), 'subminer-test-xdg-'));
-  const originalXdgDataHome = process.env.XDG_DATA_HOME;
-  try {
-    process.env.XDG_DATA_HOME = xdgDataHome;
-    const dataRoot = path.join(xdgDataHome, 'SubMiner');
-    makeFile(path.join(dataRoot, 'thumbnailers', ROFI_THUMBNAILER_FILE));
-
-    const result = withPlatform('linux', () => findRofiThumbnailerDataRoot('/usr/bin/subminer'));
-    assert.equal(result, dataRoot);
-  } finally {
-    if (originalXdgDataHome === undefined) {
-      delete process.env.XDG_DATA_HOME;
-    } else {
-      process.env.XDG_DATA_HOME = originalXdgDataHome;
-    }
-    fs.rmSync(xdgDataHome, { recursive: true, force: true });
-  }
-});
-
-test('findRofiThumbnailerDataRoot is Linux-only', () => {
-  assert.equal(
-    withPlatform('darwin', () => findRofiThumbnailerDataRoot('/usr/bin/subminer')),
-    null,
-  );
-});
-
-test('prependXdgDataDir preserves existing roots and avoids duplicates', () => {
-  const root = '/tmp/subminer-data';
-  assert.equal(
-    prependXdgDataDir(root, `/opt/share${path.delimiter}${root}${path.delimiter}/usr/share`),
-    `${root}${path.delimiter}/opt/share${path.delimiter}/usr/share`,
-  );
-  assert.equal(
-    prependXdgDataDir(root),
-    `${root}${path.delimiter}/usr/local/share${path.delimiter}/usr/share`,
-  );
-});
@@ -159,9 +159,6 @@ interface RofiIconEntry {
  iconPath?: string;
 }

-const ROFI_THUMBNAILER_FILE = 'subminer-ffmpegthumbnailer.thumbnailer';
-const DEFAULT_XDG_DATA_DIRS = ['/usr/local/share', '/usr/share'];
-
 function showRofiIconMenu(
  entries: RofiIconEntry[],
  prompt: string,
@@ -392,47 +389,6 @@ export function findRofiTheme(scriptPath: string): string | null {
  return null;
 }

-export function findRofiThumbnailerDataRoot(scriptPath: string): string | null {
-  if (process.platform !== 'linux') return null;
-
-  const scriptDir = path.dirname(realpathMaybe(scriptPath));
-  const xdgDataHome = process.env.XDG_DATA_HOME || path.join(os.homedir(), '.local/share');
-  const roots = [
-    path.join(xdgDataHome, 'SubMiner'),
-    path.posix.join('/usr/local/share/SubMiner'),
-    path.posix.join('/usr/share/SubMiner'),
-    path.join(scriptDir, 'assets'),
-    path.join(scriptDir, '..', 'assets'),
-  ];
-
-  for (const root of roots) {
-    if (fs.existsSync(path.join(root, 'thumbnailers', ROFI_THUMBNAILER_FILE))) {
-      return root;
-    }
-  }
-
-  return null;
-}
-
-export function prependXdgDataDir(dataRoot: string, currentValue?: string): string {
-  const currentDirs = currentValue
-    ? currentValue.split(path.delimiter).filter(Boolean)
-    : DEFAULT_XDG_DATA_DIRS;
-  return [dataRoot, ...currentDirs.filter((candidate) => candidate !== dataRoot)].join(
-    path.delimiter,
-  );
-}
-
-function buildRofiThumbnailEnvironment(scriptPath: string): NodeJS.ProcessEnv {
-  if (!commandExists('ffmpegthumbnailer')) return process.env;
-  const dataRoot = findRofiThumbnailerDataRoot(scriptPath);
-  if (!dataRoot) return process.env;
-  return {
-    ...process.env,
-    XDG_DATA_DIRS: prependXdgDataDir(dataRoot, process.env.XDG_DATA_DIRS),
-  };
-}
-
 export function showRofiMenu(
  videos: string[],
  dir: string,
@@ -464,7 +420,6 @@ export function showRofiMenu(
  const result = spawnSync('rofi', args, {
    input: buildRofiMenu(videos, dir, recursive),
    encoding: 'utf8',
-    env: buildRofiThumbnailEnvironment(scriptPath),
    stdio: ['pipe', 'pipe', 'ignore'],
  });
  if (result.error) {
@@ -1,8 +1,6 @@
 import test from 'node:test';
 import assert from 'node:assert/strict';
 import fs from 'node:fs';
-import os from 'node:os';
-import path from 'node:path';
 import {
  ensureLinuxRuntimePluginAvailable,
  installManagedPluginAssetsViaApp,
@@ -33,7 +31,7 @@ test('ensureLinuxRuntimePluginAvailable is a no-op on non-Linux platforms', asyn
  assert.deepEqual(calls, []);
 });

-test('ensureLinuxRuntimePluginAvailable skips install when plugin, theme, and thumbnailer exist', async () => {
+test('ensureLinuxRuntimePluginAvailable skips install when installed global plugin and managed theme exist', async () => {
  const calls: string[] = [];

  await ensureLinuxRuntimePluginAvailable({
@@ -54,17 +52,13 @@ test('ensureLinuxRuntimePluginAvailable skips install when plugin, theme, and th
      calls.push('theme');
      return true;
    },
-    isManagedThumbnailerAvailable: () => {
-      calls.push('thumbnailer');
-      return true;
-    },
    log: () => {},
  });

-  assert.deepEqual(calls, ['detect', 'theme', 'thumbnailer']);
+  assert.deepEqual(calls, ['detect', 'theme']);
 });

-test('ensureLinuxRuntimePluginAvailable skips install when all managed assets resolve', async () => {
+test('ensureLinuxRuntimePluginAvailable skips install when managed runtime path and theme already resolve', async () => {
  const calls: string[] = [];

  await ensureLinuxRuntimePluginAvailable({
@@ -86,19 +80,14 @@ test('ensureLinuxRuntimePluginAvailable skips install when all managed assets re
      calls.push('theme');
      return true;
    },
-    isManagedThumbnailerAvailable: () => {
-      calls.push('thumbnailer');
-      return true;
-    },
    log: () => {},
  });

-  assert.deepEqual(calls, ['detect', 'resolve', 'theme', 'thumbnailer']);
+  assert.deepEqual(calls, ['detect', 'resolve', 'theme']);
 });

 test('ensureLinuxRuntimePluginAvailable installs managed assets when rofi theme is missing', async () => {
  const calls: string[] = [];
-  let themeAvailable = false;

  await ensureLinuxRuntimePluginAvailable({
    platform: 'linux',
@@ -113,15 +102,10 @@ test('ensureLinuxRuntimePluginAvailable installs managed assets when rofi theme
    },
    isManagedThemeAvailable: () => {
      calls.push('theme');
-      return themeAvailable;
-    },
-    isManagedThumbnailerAvailable: () => {
-      calls.push('thumbnailer');
-      return true;
+      return false;
    },
    installManagedPluginAssets: async () => {
      calls.push('install');
-      themeAvailable = true;
      return { ok: true, status: 'installed', path: '/tmp/plugin/main.lua' };
    },
    log: (level, _configured, message) => {
@@ -133,68 +117,13 @@ test('ensureLinuxRuntimePluginAvailable installs managed assets when rofi theme
    'detect',
    'resolve',
    'theme',
-    'info:Linux runtime support assets missing; installing managed plugin/theme/thumbnailer assets.',
+    'info:Linux runtime support assets missing; installing managed plugin/theme assets.',
    'install',
-    'info:Managed Linux runtime support assets installed: plugin=/tmp/plugin/main.lua theme=/tmp/xdg-data/SubMiner/themes/subminer.rasi thumbnailer=/tmp/xdg-data/SubMiner/thumbnailers/subminer-ffmpegthumbnailer.thumbnailer',
+    'info:Managed Linux runtime support assets installed: plugin=/tmp/plugin/main.lua theme=/tmp/xdg-data/SubMiner/themes/subminer.rasi',
    'resolve',
-    'theme',
-    'thumbnailer',
  ]);
 });

-test('ensureLinuxRuntimePluginAvailable installs managed assets when thumbnailer is missing', async () => {
-  const calls: string[] = [];
-  let thumbnailerAvailable = false;
-
-  await ensureLinuxRuntimePluginAvailable({
-    platform: 'linux',
-    xdgDataHome: '/tmp/xdg-data',
-    detectInstalledPlugin: () => true,
-    resolveRuntimePluginPath: () => '/tmp/plugin/main.lua',
-    isManagedThemeAvailable: () => true,
-    isManagedThumbnailerAvailable: () => thumbnailerAvailable,
-    installManagedPluginAssets: async () => {
-      calls.push('install');
-      thumbnailerAvailable = true;
-      return { ok: true, status: 'installed', path: '/tmp/plugin/main.lua' };
-    },
-    log: (_level, _configured, message) => {
-      calls.push(message);
-    },
-  });
-
-  assert.deepEqual(calls, [
-    'Linux runtime support assets missing; installing managed plugin/theme/thumbnailer assets.',
-    'install',
-    'Managed Linux runtime support assets installed: plugin=/tmp/plugin/main.lua theme=/tmp/xdg-data/SubMiner/themes/subminer.rasi thumbnailer=/tmp/xdg-data/SubMiner/thumbnailers/subminer-ffmpegthumbnailer.thumbnailer',
-  ]);
-});
-
-test('ensureLinuxRuntimePluginAvailable retains an installed plugin after installing support assets', async () => {
-  const calls: string[] = [];
-  let thumbnailerAvailable = false;
-
-  await ensureLinuxRuntimePluginAvailable({
-    platform: 'linux',
-    xdgDataHome: '/tmp/xdg-data',
-    detectInstalledPlugin: () => true,
-    resolveRuntimePluginPath: () => {
-      calls.push('resolve');
-      return null;
-    },
-    isManagedThemeAvailable: () => true,
-    isManagedThumbnailerAvailable: () => thumbnailerAvailable,
-    installManagedPluginAssets: async () => {
-      calls.push('install');
-      thumbnailerAvailable = true;
-      return { ok: true, status: 'installed', path: '/tmp/plugin/main.lua' };
-    },
-    log: () => {},
-  });
-
-  assert.deepEqual(calls, ['install']);
-});
-
 test('ensureLinuxRuntimePluginAvailable installs managed assets and re-resolves plugin path', async () => {
  const calls: string[] = [];
  let resolveCount = 0;
@@ -208,8 +137,6 @@ test('ensureLinuxRuntimePluginAvailable installs managed assets and re-resolves
      calls.push(`resolve:${resolveCount}`);
      return resolveCount === 1 ? null : '/tmp/plugin/main.lua';
    },
-    isManagedThemeAvailable: () => true,
-    isManagedThumbnailerAvailable: () => true,
    installManagedPluginAssets: async () => {
      calls.push('install');
      return { ok: true, status: 'installed', path: '/tmp/plugin/main.lua' };
@@ -221,9 +148,9 @@ test('ensureLinuxRuntimePluginAvailable installs managed assets and re-resolves

  assert.deepEqual(calls, [
    'resolve:1',
-    'info:Linux runtime support assets missing; installing managed plugin/theme/thumbnailer assets.',
+    'info:Linux runtime support assets missing; installing managed plugin/theme assets.',
    'install',
-    'info:Managed Linux runtime support assets installed: plugin=/tmp/plugin/main.lua theme=/tmp/xdg-data/SubMiner/themes/subminer.rasi thumbnailer=/tmp/xdg-data/SubMiner/thumbnailers/subminer-ffmpegthumbnailer.thumbnailer',
+    'info:Managed Linux runtime support assets installed: plugin=/tmp/plugin/main.lua theme=/tmp/xdg-data/SubMiner/themes/subminer.rasi',
    'resolve:2',
  ]);
 });
@@ -264,60 +191,6 @@ test('ensureLinuxRuntimePluginAvailable fails when runtime path remains unresolv
  );
 });

-test('ensureLinuxRuntimePluginAvailable fails when thumbnailer remains missing after install', async () => {
-  await assert.rejects(
-    () =>
-      ensureLinuxRuntimePluginAvailable({
-        platform: 'linux',
-        xdgDataHome: '/tmp/xdg-data',
-        detectInstalledPlugin: () => true,
-        resolveRuntimePluginPath: () => '/tmp/plugin/main.lua',
-        isManagedThemeAvailable: () => true,
-        isManagedThumbnailerAvailable: () => false,
-        installManagedPluginAssets: async () => ({
-          ok: true,
-          status: 'installed',
-          path: '/tmp/plugin/main.lua',
-        }),
-        log: () => {},
-      }),
-    /thumbnailer=.*subminer-ffmpegthumbnailer\.thumbnailer/i,
-  );
-});
-
-test('ensureLinuxRuntimePluginAvailable rejects a thumbnailer directory before and after install', async () => {
-  const xdgDataHome = fs.mkdtempSync(path.join(os.tmpdir(), 'subminer-thumbnailer-directory-'));
-  const thumbnailerPath = path.join(
-    xdgDataHome,
-    'SubMiner',
-    'thumbnailers',
-    'subminer-ffmpegthumbnailer.thumbnailer',
-  );
-  fs.mkdirSync(thumbnailerPath, { recursive: true });
-  const calls: string[] = [];
-
-  try {
-    await assert.rejects(
-      () =>
-        ensureLinuxRuntimePluginAvailable({
-          platform: 'linux',
-          xdgDataHome,
-          detectInstalledPlugin: () => true,
-          isManagedThemeAvailable: () => true,
-          installManagedPluginAssets: async () => {
-            calls.push('install');
-            return { ok: true, status: 'installed', path: '/tmp/plugin/main.lua' };
-          },
-          log: () => {},
-        }),
-      /thumbnailer=.*subminer-ffmpegthumbnailer\.thumbnailer/i,
-    );
-    assert.deepEqual(calls, ['install']);
-  } finally {
-    fs.rmSync(xdgDataHome, { recursive: true, force: true });
-  }
-});
-
 test('installManagedPluginAssetsViaApp returns launch errors without waiting for a response file', async () => {
  let waited = false;

@@ -31,7 +31,6 @@ type EnsureLinuxRuntimePluginAvailableOptions = {
  detectInstalledPlugin?: () => boolean;
  resolveRuntimePluginPath?: () => string | null;
  isManagedThemeAvailable?: () => boolean;
-  isManagedThumbnailerAvailable?: () => boolean;
  installManagedPluginAssets?: () => Promise<EnsureLinuxRuntimePluginAssetsResult>;
  log?: PreflightLog;
 };
@@ -49,14 +48,6 @@ function resolveConfiguredLogLevel(
  return logLevel ?? 'warn';
 }

-function isRegularFile(filePath: string): boolean {
-  try {
-    return fs.statSync(filePath).isFile();
-  } catch {
-    return false;
-  }
-}
-
 async function waitForInstallResponse(
  responsePath: string,
 ): Promise<RuntimePluginPreflightResponse | null> {
@@ -179,17 +170,15 @@ export async function ensureLinuxRuntimePluginAvailable(
    });
  const isManagedThemeAvailable =
    options.isManagedThemeAvailable ?? (() => fs.existsSync(managedPaths.themePath));
-  const isManagedThumbnailerAvailable =
-    options.isManagedThumbnailerAvailable ?? (() => isRegularFile(managedPaths.thumbnailerPath));
  const runtimePluginAvailable = installedPluginAvailable || Boolean(resolveRuntimePluginPath());
-  if (runtimePluginAvailable && isManagedThemeAvailable() && isManagedThumbnailerAvailable()) {
+  if (runtimePluginAvailable && isManagedThemeAvailable()) {
    return;
  }

  log(
    'info',
    configuredLogLevel,
-    'Linux runtime support assets missing; installing managed plugin/theme/thumbnailer assets.',
+    'Linux runtime support assets missing; installing managed plugin/theme assets.',
  );
  const installManagedPluginAssets =
    options.installManagedPluginAssets ??
@@ -218,21 +207,16 @@ export async function ensureLinuxRuntimePluginAvailable(
  log(
    'info',
    configuredLogLevel,
-    `Managed Linux runtime support assets installed: plugin=${installResult.path ?? 'unknown path'} theme=${managedPaths.themePath} thumbnailer=${managedPaths.thumbnailerPath}`,
+    `Managed Linux runtime support assets installed: plugin=${installResult.path ?? 'unknown path'} theme=${managedPaths.themePath}`,
  );
-  const runtimePluginAvailableAfterInstall =
-    installedPluginAvailable || Boolean(resolveRuntimePluginPath());
-  if (
-    runtimePluginAvailableAfterInstall &&
-    isManagedThemeAvailable() &&
-    isManagedThumbnailerAvailable()
-  ) {
+  const runtimePluginPath = resolveRuntimePluginPath();
+  if (runtimePluginPath) {
    return;
  }

  const message =
    `Linux managed runtime plugin assets could not be installed. ` +
-    `Checked paths: plugin=${managedPaths.pluginEntrypointPath} theme=${managedPaths.themePath} thumbnailer=${managedPaths.thumbnailerPath}. ` +
+    `Checked path: ${managedPaths.pluginEntrypointPath}. ` +
    'Launch aborted before starting mpv.';
  log('warn', configuredLogLevel, message);
  throw new Error(message);
@@ -165,14 +165,11 @@ if (entry.argv.includes('--ensure-linux-runtime-plugin-assets')) {
  const pluginDir = path.join(dataDir, 'plugin', 'subminer');
  const pluginConfigPath = path.join(dataDir, 'plugin', 'subminer.conf');
  const themePath = path.join(dataDir, 'themes', 'subminer.rasi');
-  const thumbnailerPath = path.join(dataDir, 'thumbnailers', 'subminer-ffmpegthumbnailer.thumbnailer');
  fs.mkdirSync(pluginDir, { recursive: true });
  fs.mkdirSync(path.dirname(themePath), { recursive: true });
-  fs.mkdirSync(path.dirname(thumbnailerPath), { recursive: true });
  fs.writeFileSync(path.join(pluginDir, 'main.lua'), '-- smoke plugin\\n');
  fs.writeFileSync(pluginConfigPath, 'smoke=true\\n');
  fs.writeFileSync(themePath, '/* smoke theme */\\n');
-  fs.writeFileSync(thumbnailerPath, '[Thumbnailer Entry]\\n');
  if (responsePath) {
    fs.mkdirSync(path.dirname(responsePath), { recursive: true });
    fs.writeFileSync(responsePath, JSON.stringify({ ok: true, status: 'installed', path: path.join(pluginDir, 'main.lua') }));
@@ -623,22 +620,11 @@ test(
      );
      assert.match(result.stdout, /pause mpv until overlay and tokenization are ready/i);
      if (process.platform === 'linux') {
-        assert.match(result.stdout, /managed plugin\/theme\/thumbnailer assets/i);
+        assert.match(result.stdout, /managed plugin\/theme assets/i);
        assert.equal(
          fs.existsSync(path.join(smokeCase.xdgDataHome, 'SubMiner', 'themes', 'subminer.rasi')),
          true,
        );
-        assert.equal(
-          fs.existsSync(
-            path.join(
-              smokeCase.xdgDataHome,
-              'SubMiner',
-              'thumbnailers',
-              'subminer-ffmpegthumbnailer.thumbnailer',
-            ),
-          ),
-          true,
-        );
      }
    });
  },
@@ -2,7 +2,7 @@
  "name": "subminer",
  "productName": "SubMiner",
  "desktopName": "SubMiner.desktop",
-  "version": "0.19.4-beta.3",
+  "version": "0.19.4-beta.1",
  "description": "All-in-one sentence mining overlay with AnkiConnect and dictionary integration",
  "packageManager": "bun@1.3.5",
  "main": "dist/main-entry.js",
@@ -125,7 +125,7 @@
  "devDependencies": {
    "@types/node": "^24.10.0",
    "@types/ws": "^8.18.1",
-    "electron": "42.6.0",
+    "electron": "43.4.1",
    "electron-builder": "26.15.3",
    "undici": "7.29.0",
    "esbuild": "^0.25.12",
@@ -58,8 +58,6 @@ package() {
 		"${pkgdir}/usr/share/SubMiner/plugin/subminer.conf"
 	install -Dm644 "${srcdir}/assets/themes/subminer.rasi" \
 		"${pkgdir}/usr/share/SubMiner/themes/subminer.rasi"
-	install -Dm644 "${srcdir}/assets/thumbnailers/subminer-ffmpegthumbnailer.thumbnailer" \
-		"${pkgdir}/usr/share/SubMiner/thumbnailers/subminer-ffmpegthumbnailer.thumbnailer"

 	install -dm755 "${pkgdir}/usr/share/SubMiner/plugin/subminer"
 	cp -a "${srcdir}/plugin/subminer/." "${pkgdir}/usr/share/SubMiner/plugin/subminer/"
@@ -4,44 +4,37 @@

 ## Highlights
 ### Added
-
- Library Merge & Reassignment
-  - Duplicate library entries for the same show can now be merged: pick entries in "Select" mode and use "Merge Selected" to combine their sessions, mined cards, and watch time onto one card.
-  - Episodes can be moved to a different library entry with a per-episode "→" button, fixing cases where a stray filename split off its own entry; manual assignments now survive later filename parsing, Jellyfin refreshes, and season repair, and other episodes in the same folder pick up the same fix automatically unless they already belong elsewhere.
-  - Exact AniList matches with compatible seasons now merge automatically, and likely (fuzzy) matches surface as a dismissible "Possible duplicate" suggestion instead of merging silently; entries with conflicting seasons are left alone either way.
-
- Duplicate Line Cleanup
-  - The Vocabulary tab's new **Duplicates** button scans a chosen time window for the repeated-line bursts described under Fixed below and collapses each burst to a single line once you confirm it; a matching `subminer stats cleanup --duplicate-lines` command (with `--dry-run` and `--lookback-days <n>`) is available from the terminal.
-  - Only the affected subtitle lines and the vocabulary counts they inflated are touched; watch time and lines-seen totals are left as recorded.
+- **Library Merge and Move**
+  - Duplicate library cards for the same show can now be combined: select cards in the library grid, choose "Merge Selected," and pick which entry to keep. Sessions, mined cards, and watch time move over, and future episodes stay matched to the merged card.
+  - Episodes can be reassigned to a different library entry with a "→" button on the episode row, fixing cases where a file lands under the wrong title. Manual assignments survive later filename parsing, Jellyfin refreshes, and season repair.
+  - Exact AniList matches with compatible seasons now merge automatically, while fuzzy matches show up as a dismissible "Possible duplicate" prompt instead of merging without confirmation.

 ### Fixed
+- **Anki Audio Generation on Network Drives**
+  - Fixed sentence-audio generation timing out on slow network-mounted video files with many subtitle and font-attachment streams.
+  - Extraction now uses bounded probing and a two-minute budget, and failures show a clear error instead of a cryptic one.
+- **Duplicate Subtitle Line Stats**
+  - Fixed karaoke openings and animated signs (which record one subtitle event per animation frame) inflating word and kanji counts and skewing "Top Repeated Words." Ordinary repeated dialogue and rewatches are unaffected.
+  - Already-inflated stats can be cleaned up with the new "Duplicates" button in the Vocabulary tab, or `subminer stats cleanup --duplicate-lines` (supports `--dry-run` and `--lookback-days`). Only the affected subtitle lines and vocabulary counts are touched; watch time and lines-seen totals are untouched.
+- **Overlay Modals on macOS and Windows**
+  - Fixed overlay modals and the stats window opening on the wrong macOS Space, or forcing a Space switch, when mpv is fullscreen. They now open above fullscreen mpv on its current Space.
+  - Modals are now prewarmed on macOS and Windows so shortcuts open them promptly, and Windows keeps the hidden modal responsive between sessions.
+- **Wayland File Drag-and-Drop**
+  - Fixed dragging subtitle and video files from file managers like Thunar onto the overlay on native Wayland; dropped files are now resolved and sent to mpv.
+- **Windows Mouse Lag**
+  - Fixed system-wide mouse lag while SubMiner is running on Windows, caused by a global mouse hook and blocking window lookups during click-through tracking.
+- **Mining Clip Accuracy**
+  - Fixed mined audio and animated image clips sometimes capturing the wrong subtitle line when audio extraction was slow. The clip range is now locked in at the moment of lookup, so audio and image clips always match.
+- **Linux Notifications**
+  - Character dictionary progress notifications on Linux now update in place instead of flickering off and back on with every status change.
+- **Stats Delete Performance**
+  - Fixed stats deletes freezing the dashboard; deletes now reliably run off the main thread, with automatic retry if the delete worker crashes.
+  - Deletes, library merges/moves, and AniList reassignments are now much faster because totals are updated incrementally instead of rebuilt from scratch, and no longer erase lifetime totals older than the recent session history.
+  - Session deletes on large libraries dropped from minutes to milliseconds.

- Subtitle Duplication from Karaoke & Animated Signs
-  - Typeset ASS karaoke and animated signs no longer flood the overlay, subtitle sidebar, immersion history, mined cards, or stats with repeated glyph fragments or per-frame duplicates; the complete authored line is recovered instead, without merging genuinely repeated dialogue or separately positioned signs. Dialogue spoken while a song's animation is on screen is kept intact instead of being replaced by the lyric, and lyric transitions (including seeking into the middle of a line) resolve to the clean line instead of a stray entrance or exit frame.
-  - The secondary overlay now shares the same deduplication logic as the primary overlay, including collapsing lines that only differ by whitespace or trailing punctuation, so layered animation text and dense multi-row sign layouts no longer appear duplicated or garbled there or in what gets mined.
-  - Sidebar navigation now moves between the clean, sanitized lyric lines instead of the raw generated animation events, and selecting an overlapping lyric keeps the right line selected.
-  - Vocabulary stats no longer count every animation frame of a karaoke opening as a separate line, which previously could push an OP lyric to the top of "Top Repeated Words."
-
- Anki Media Generation
-  - Sentence-audio generation no longer times out on slow network-mounted video files with many subtitle and font streams (bounded probing plus a two-minute extraction budget), and a failed extraction now reports a clear error instead of a raw `ENOENT`.
-  - Mined audio and animated AVIF clips now capture the subtitle line you actually mined, instead of whatever line happened to be on screen once slow audio extraction finished.
-
- Character Dictionary Performance & Notifications
-  - Character dictionary generation, merged rebuilds, and imports no longer freeze the app on large dictionaries, and cached results (including character portraits) are reused across launches instead of regenerating everything every time. Portraits also now display correctly if their cache finishes loading after subtitles have already started showing.
-  - Desktop progress notifications, including on Linux AppImage installs, now update in place instead of flickering closed and reopening.
-
- Overlay Reliability
-  - Overlay modals (settings, stats, etc.) now open promptly on the first shortcut press, including on repeated sessions on Windows, and appear above fullscreen mpv on macOS instead of switching Spaces or opening off-screen.
-  - The overlay no longer gets stuck on "Overlay loading" indefinitely if mpv's connection stalls; it now retries and shows an actionable error after 30 seconds.
-  - Fixed native Wayland drag-and-drop from file managers like Thunar, so subtitle and video files dropped on the overlay reach mpv.
-  - Fixed system-wide mouse lag on Windows caused by the overlay's click-through handling and repeated mpv window lookups.
-
- Stats Dashboard
-  - Deletes, library merges, video moves, and AniList reassignments no longer freeze the stats dashboard or rebuild lifetime totals from scratch; large deletes that used to take minutes now finish in milliseconds.
-  - Vocabulary totals and charts now count all tracked vocabulary instead of just the first page, new-word history uses corrected daily rollups, calendar labels respect time zones west of UTC, and vocabulary cards refresh automatically after editing the word exclusion list (with a Retry option if a load fails).
-
- Linux Launcher Thumbnails
-  - Fixed missing MKV thumbnails in the Linux rofi picker when the system thumbnailer only registers legacy Matroska MIME aliases.
+### Docs
+- **Feature Demos Page**
+  - Hidden the unfinished feature demos page from the documentation sidebar; it's still reachable by direct URL.

 ## What's Changed

@@ -54,13 +47,6 @@
 - fix(overlay): support native Wayland file drag-and-drop by @ksyasuda in #199
 - fix(overlay): keep macOS modal windows on fullscreen Spaces by @ksyasuda in #200
 - fix(overlay): prevent Windows mouse lag during click-through tracking by @ksyasuda in #201
- fix(stats): report complete vocabulary totals and new-word history by @ksyasuda in #202
- fix(mpv): recover from stalled IPC connects by @ksyasuda in #204
- fix(dictionary): prevent freezes and restore AppImage notifications by @ksyasuda in #205
- fix(subtitles): recover canonical lines from ASS animation by @ksyasuda in #207
- fix(overlay): deduplicate secondary subtitle rendering by @ksyasuda in #208
- fix(launcher): restore Matroska thumbnails in Linux rofi picker by @ksyasuda in #210
- fix(character-dictionary): cache completed MeCab refreshes by @ksyasuda in #212

 ## Installation

@@ -1,17 +0,0 @@
-#!/usr/bin/env bash
-
-set -euo pipefail
-
-FILE="${1:-}"
-
-if [[ ! -f "$FILE" ]]; then
-	printf 'Not a file: %s\n' "${FILE:-<missing>}" >&2
-	exit 1
-fi
-
-if ! mpv --no-config --no-terminal --msg-level=all=no --vo=null --ao=null --frames=1 -- "$FILE"; then
-	printf 'Not playable by mpv: %s\n' "$FILE" >&2
-	exit 1
-fi
-
-exec subminer app --dev --launch-mpv "$FILE"
@@ -19,8 +19,7 @@ Options:
  -w, --webp   Generate animated WebP preview

 Encoding profile:
-  - Crop: mpv region at 1920x1080, x=760 y=205 on a 3440x1440 canvas
-  - Output size: 1920x1080
+  - Crop: 1920x1080 at x=760 y=200
  - MP4:  H.264 + AAC
  - WebM: AV1/VP9 + Opus at 30 fps
 USAGE
@@ -149,8 +148,7 @@ pick_webp_encoder() {
 	return 1
 }

-# OBS may resize the 3440x1440 canvas, so scale the mpv bounds with the input.
-crop_vf="crop=1920*iw/3440:1080*ih/1440:760*iw/3440:205*ih/1440,scale=1920:1080:flags=lanczos"
+crop_vf="crop=1920:1080:760:205"
 webm_vf="${crop_vf},fps=30"

 echo "Generating MP4: $mp4_out"
@@ -40,7 +40,7 @@ function toBashPath(filePath: string): string {
  return `${drive.toUpperCase()}:/${rest}`;
 }

-test('mkv-to-readme-video builds every output with the scaled mpv crop', () => {
+test('mkv-to-readme-video accepts libwebp_anim when libwebp is unavailable', () => {
  withTempDir((root) => {
    const binDir = path.join(root, 'bin');
    const inputPath = path.join(root, 'sample.mkv');
@@ -104,9 +104,5 @@ touch "$output"

    const ffmpegLog = fs.readFileSync(ffmpegLogPath, 'utf8');
    assert.match(ffmpegLog, /-c:v libwebp_anim/);
-    const scaledCropUses = ffmpegLog.match(
-      /-vf crop=1920\*iw\/3440:1080\*ih\/1440:760\*iw\/3440:205\*ih\/1440,scale=1920:1080:flags=lanczos/g,
-    );
-    assert.equal(scaledCropUses?.length, 4);
  });
 });
@@ -82,7 +82,6 @@ test('update-aur-package updates PKGBUILD and .SRCINFO without makepkg', () => {
      pkgbuild,
      /^\s*install -Dm755 "\$\{srcdir\}\/subminer-\$\{pkgver\}" "\$\{pkgdir\}\/usr\/bin\/subminer"$/m,
    );
-    assert.match(pkgbuild, /assets\/thumbnailers\/subminer-ffmpegthumbnailer\.thumbnailer/);
    assert.match(srcinfo, /^\tpkgver = 0\.6\.3$/m);
    assert.match(srcinfo, /^\tprovides = subminer=0\.6\.3$/m);
    assert.match(
@@ -47,7 +47,7 @@ test('stripFilenameTags normalizes common media-title formats', () => {
  );
 });

-test('fetchIfMissing backfills a missing blob from an existing cover URL', async () => {
+async function backfillMissingCoverBlob(): Promise<void> {
  const dbPath = makeDbPath();
  const db = new Database(dbPath);
  ensureSchema(db);
@@ -103,9 +103,15 @@ test('fetchIfMissing backfills a missing blob from an existing cover URL', async
    db.close();
    cleanupDbPath(dbPath);
  }
-});
+}

-test('fetchIfMissing reuses cached cover art from another video in the same anime', async () => {
+test(
+  'fetchIfMissing backfills a missing blob from an existing cover URL',
+  { timeout: 15_000 },
+  backfillMissingCoverBlob,
+);
+
+async function reuseCachedAnimeCoverArt(): Promise<void> {
  const dbPath = makeDbPath();
  const db = new Database(dbPath);
  ensureSchema(db);
@@ -179,7 +185,13 @@ test('fetchIfMissing reuses cached cover art from another video in the same anim
    db.close();
    cleanupDbPath(dbPath);
  }
-});
+}
+
+test(
+  'fetchIfMissing reuses cached cover art from another video in the same anime',
+  { timeout: 15_000 },
+  reuseCachedAnimeCoverArt,
+);

 function createJsonResponse(payload: unknown): Response {
  return new Response(JSON.stringify(payload), {
@@ -50,11 +50,6 @@ export {
 } from './tokenizer/yomitan-parser-runtime';
 export { syncYomitanDefaultAnkiServer } from './tokenizer/yomitan-parser-runtime';
 export { createSubtitleProcessingController } from './subtitle-processing-controller';
-export {
-  resolveSanitizedSubtitleSeekCommand,
-  subtitleCueListSeekTime,
-  subtitleCueSeekTime,
-} from './subtitle-cue-navigation';
 export { createFrequencyDictionaryLookup } from './frequency-dictionary';
 export { createJlptVocabularyLookup } from './jlpt-vocab';
 export {
@@ -39,6 +39,7 @@ test('non-macOS modal overlay remains a regular window', () => {
  });

  assert.equal(options.type, undefined);
+  assert.equal(options.roundedCorners, false);
 });

 test('Linux visible overlay window allows compositor resize for mpv-sized placement', () => {
@@ -37,6 +37,7 @@ export function buildOverlayWindowOptions(
    paintWhenInitiallyHidden: true,
    backgroundColor: '#00000000',
    frame: false,
+    ...(platform === 'linux' ? { roundedCorners: false } : {}),
    alwaysOnTop: shouldStartAlwaysOnTop,
    skipTaskbar: true,
    resizable: shouldAllowCompositorResize,
@@ -1,15 +0,0 @@
-const MIN_FLATTENED_DUPLICATE_LENGTH = 16;
-const TERMINAL_SENTENCE_PUNCTUATION = /[.!?。！？…⋯]+$/gu;
-
-/**
- * Identifies long lines that become duplicates when positioned ASS events are
- * flattened into the secondary subtitle bar. Short dialogue stays distinct.
- */
-export function flattenedSecondarySubtitleLineIdentity(text: string): string | null {
-  const identity = text
-    .normalize('NFKC')
-    .replace(/\s+/gu, '')
-    .replace(TERMINAL_SENTENCE_PUNCTUATION, '');
-
-  return identity.length >= MIN_FLATTENED_DUPLICATE_LENGTH ? identity : null;
-}
@@ -67,6 +67,7 @@ export function buildStatsWindowOptions(options: {
    width: options.bounds?.width ?? DEFAULT_STATS_WINDOW_WIDTH,
    height: options.bounds?.height ?? DEFAULT_STATS_WINDOW_HEIGHT,
    frame: false,
+    ...(platform === 'linux' ? { roundedCorners: false } : {}),
    transparent: false,
    alwaysOnTop: true,
    resizable: false,
@@ -57,6 +57,7 @@ test('buildStatsWindowOptions remains a regular window off macOS', () => {
  });

  assert.equal(options.type, undefined);
+  assert.equal(options.roundedCorners, false);
 });

 test('stats panels present after document load on macOS', () => {
@@ -149,8 +149,8 @@ function collectRepeatedPhaseRuns(cues: AnnotatedSubtitleCue[]): RepeatedPhaseRu
      const isFlush =
        Math.abs(next.startTime - current.endTime) <= DUPLICATE_CUE_GAP_TOLERANCE_SECONDS;
      if (
-        first.source !== undefined ||
-        next.source !== undefined ||
+        first.source === 'canonical-ass' ||
+        next.source === 'canonical-ass' ||
        next.text !== first.text ||
        assStyleKey(next) !== styleKey ||
        !isFlush
@@ -223,7 +223,7 @@ function countFramesShorterThan(run: AnnotatedSubtitleCue[], maxSeconds: number)
 * anything wrapped in `\t(...)`), an animated `Effect` column, or a value that actually
 * changes from event to event, which is how per-frame typesetting is authored.
 */
-export function hasAssAnimationEvidence(run: readonly AnnotatedSubtitleCue[]): boolean {
+export function hasAssAnimationEvidence(run: AnnotatedSubtitleCue[]): boolean {
  if (run.every((cue) => hasAssTemporalOverride(cue.overrides))) {
    return true;
  }
@@ -1,108 +0,0 @@
-import assert from 'node:assert/strict';
-import test from 'node:test';
-import {
-  resolveSanitizedSubtitleSeekCommand,
-  subtitleCueListSeekTime,
-  subtitleCueSeekTime,
-} from './subtitle-cue-navigation';
-
-test('next subtitle navigation skips generated ASS events and seeks to the next sanitized cue', () => {
-  const cues = [
-    {
-      startTime: 10,
-      endTime: 13,
-      text: 'first lyric',
-      source: 'canonical-ass' as const,
-      animationStartTime: 9.7,
-      animationEndTime: 13.4,
-    },
-    {
-      startTime: 13,
-      endTime: 16,
-      text: 'second lyric',
-      source: 'canonical-ass' as const,
-      animationStartTime: 12.7,
-      animationEndTime: 16.4,
-    },
-  ];
-
-  assert.deepEqual(resolveSanitizedSubtitleSeekCommand(['sub-seek', 1], cues, 10.2), [
-    'seek',
-    13.08,
-    'absolute+exact',
-  ]);
-});
-
-test('next subtitle navigation treats simultaneous sanitized cues as one line boundary', () => {
-  const cues = [
-    { startTime: 10, endTime: 13, text: 'romaji' },
-    { startTime: 10.02, endTime: 13, text: 'English' },
-    { startTime: 13, endTime: 16, text: 'next romaji' },
-    { startTime: 13.02, endTime: 16, text: 'Next English' },
-  ];
-
-  assert.deepEqual(resolveSanitizedSubtitleSeekCommand(['sub-seek', 1], cues, 10.1), [
-    'seek',
-    13.08,
-    'absolute+exact',
-  ]);
-});
-
-test('next subtitle navigation advances past the latest overlapping lyric', () => {
-  const cues = [
-    { startTime: 10, endTime: 14, text: 'exiting lyric' },
-    { startTime: 13, endTime: 16, text: 'current lyric' },
-    { startTime: 16, endTime: 19, text: 'next lyric' },
-  ];
-
-  assert.deepEqual(resolveSanitizedSubtitleSeekCommand(['sub-seek', 1], cues, 13.2), [
-    'seek',
-    16.08,
-    'absolute+exact',
-  ]);
-});
-
-test('previous subtitle navigation leaves the current cue and seeks to the prior cue', () => {
-  const cues = [
-    { startTime: 10, endTime: 12, text: 'first line' },
-    { startTime: 13, endTime: 16, text: 'current line' },
-  ];
-
-  assert.deepEqual(resolveSanitizedSubtitleSeekCommand(['sub-seek', -1], cues, 14.5), [
-    'seek',
-    10.08,
-    'absolute+exact',
-  ]);
-});
-
-test('subtitle navigation falls back when no sanitized destination exists', () => {
-  const cues = [{ startTime: 10, endTime: 13, text: 'only line' }];
-
-  assert.equal(resolveSanitizedSubtitleSeekCommand(['sub-seek', 1], cues, 10.2), null);
-  assert.equal(resolveSanitizedSubtitleSeekCommand(['seek', 5], cues, 10.2), null);
-});
-
-test('sidebar cue seeks share the boundary-safe sanitized cue timestamp', () => {
-  assert.equal(subtitleCueSeekTime({ startTime: 1, endTime: 2, text: 'line' }), 1.08);
-  assert.equal(subtitleCueSeekTime({ startTime: 1, endTime: 1.04, text: 'short' }), 1.03);
-});
-
-test('sidebar cue selection clears an overlapping previous lyric', () => {
-  const cues = [
-    { startTime: 1, endTime: 3.4, text: 'previous lyric' },
-    { startTime: 3, endTime: 5, text: 'selected lyric' },
-  ];
-
-  assert.equal(subtitleCueListSeekTime(cues, cues[1]!), 3.48);
-});
-
-test('sidebar cue selection remains inside a short cue when overlap cannot be cleared', () => {
-  const cues = [
-    { startTime: 1, endTime: 3.4, text: 'previous lyric' },
-    { startTime: 3, endTime: 3.2, text: 'selected lyric' },
-  ];
-
-  const seekTime = subtitleCueListSeekTime(cues, cues[1]!);
-  assert.ok(seekTime >= 3.19);
-  assert.ok(seekTime < cues[1]!.endTime);
-});
@@ -1,128 +0,0 @@
-import type { SubtitleCue } from './subtitle-cue-parser';
-
-const CUE_START_GROUP_TOLERANCE_SECONDS = 0.05;
-const CUE_BOUNDARY_SEEK_OFFSET_SECONDS = 0.08;
-const CUE_END_GUARD_SECONDS = 0.01;
-
-type CueGroup = {
-  startTime: number;
-  endTime: number;
-  cue: SubtitleCue;
-};
-
-function isValidCue(cue: SubtitleCue): boolean {
-  return (
-    Number.isFinite(cue.startTime) && Number.isFinite(cue.endTime) && cue.endTime > cue.startTime
-  );
-}
-
-function groupCueBoundaries(cues: readonly SubtitleCue[]): CueGroup[] {
-  const sorted = cues.filter(isValidCue).sort((left, right) => {
-    return left.startTime - right.startTime || left.endTime - right.endTime;
-  });
-  const groups: CueGroup[] = [];
-
-  for (const cue of sorted) {
-    const current = groups.at(-1);
-    if (current && cue.startTime - current.startTime <= CUE_START_GROUP_TOLERANCE_SECONDS) {
-      current.endTime = Math.max(current.endTime, cue.endTime);
-      continue;
-    }
-    groups.push({ startTime: cue.startTime, endTime: cue.endTime, cue });
-  }
-
-  return groups;
-}
-
-/** A small offset avoids asking mpv to render exactly on a subtitle boundary. */
-export function subtitleCueSeekTime(cue: SubtitleCue): number {
-  return Math.max(
-    cue.startTime,
-    Math.min(cue.endTime - CUE_END_GUARD_SECONDS, cue.startTime + CUE_BOUNDARY_SEEK_OFFSET_SECONDS),
-  );
-}
-
-/**
- * Choose a stable point inside a selected cue. Karaoke lines can overlap while the
- * previous line animates out, so a sidebar selection should clear that overlap when
- * the selected cue has enough time remaining.
- */
-export function subtitleCueListSeekTime(
-  cues: readonly SubtitleCue[],
-  selectedCue: SubtitleCue,
-): number {
-  const groups = groupCueBoundaries(cues);
-  const selectedGroupIndex = groups.findIndex(
-    (group) =>
-      selectedCue.startTime >= group.startTime &&
-      selectedCue.startTime - group.startTime <= CUE_START_GROUP_TOLERANCE_SECONDS,
-  );
-  const previousGroupEndTime =
-    selectedGroupIndex > 0 ? groups[selectedGroupIndex - 1]?.endTime : undefined;
-  if (previousGroupEndTime === undefined || previousGroupEndTime <= selectedCue.startTime) {
-    return subtitleCueSeekTime(selectedCue);
-  }
-
-  return Math.max(
-    selectedCue.startTime,
-    Math.min(
-      selectedCue.endTime - CUE_END_GUARD_SECONDS,
-      previousGroupEndTime + CUE_BOUNDARY_SEEK_OFFSET_SECONDS,
-    ),
-  );
-}
-
-/**
- * Translate mpv subtitle-line navigation onto parsed cues. Generated ASS karaoke can
- * contain hundreds of subtitle events for one visible line, while the parsed list has
- * already collapsed those events into the authored lines the user expects to navigate.
- */
-export function resolveSanitizedSubtitleSeekCommand(
-  command: readonly (string | number)[],
-  cues: readonly SubtitleCue[],
-  currentTimeSec: number,
-): (string | number)[] | null {
-  if (
-    command.length < 2 ||
-    command[0] !== 'sub-seek' ||
-    (command[1] !== -1 && command[1] !== 1) ||
-    !Number.isFinite(currentTimeSec)
-  ) {
-    return null;
-  }
-
-  const groups = groupCueBoundaries(cues);
-  if (groups.length === 0) {
-    return null;
-  }
-
-  let activeIndex = -1;
-  for (const [index, group] of groups.entries()) {
-    if (group.startTime <= currentTimeSec && group.endTime > currentTimeSec) {
-      activeIndex = index;
-    }
-  }
-
-  let destination: CueGroup | undefined;
-  if (command[1] === 1) {
-    destination =
-      activeIndex >= 0
-        ? groups[activeIndex + 1]
-        : groups.find((group) => group.startTime > currentTimeSec);
-  } else if (activeIndex >= 0) {
-    destination = groups[activeIndex - 1];
-  } else {
-    for (let index = groups.length - 1; index >= 0; index -= 1) {
-      const group = groups[index]!;
-      if (group.startTime < currentTimeSec) {
-        destination = group;
-        break;
-      }
-    }
-  }
-
-  if (!destination) {
-    return null;
-  }
-  return ['seek', subtitleCueSeekTime(destination.cue), 'absolute+exact'];
-}
@@ -570,63 +570,6 @@ test('parseSubtitleCues does not promote a short animated fragment as a complete
  );
 });

-test('parseSubtitleCues keeps short animated English dialogue as separate cues', () => {
-  const content = [
-    '[Events]',
-    'Format: Layer, Start, End, Style, Name, MarginL, MarginR, MarginV, Effect, Text',
-    'Dialogue: 0,0:00:01.00,0:00:02.00,English Dialogue,,0,0,0,,{\\t(0,100,\\fscx110)}Hi',
-    'Dialogue: 0,0:00:02.00,0:00:03.00,English Dialogue,,0,0,0,,{\\t(0,100,\\fscx110)}No',
-  ].join('\n');
-
-  assert.deepEqual(parseSubtitleCues(content, 'test.ass'), [
-    { startTime: 1, endTime: 2, text: 'Hi' },
-    { startTime: 2, endTime: 3, text: 'No' },
-  ]);
-});
-
-test('parseSubtitleCues does not reconstruct an already canonical English cue', () => {
-  const content = [
-    '[Events]',
-    'Format: Layer, Start, End, Style, Name, MarginL, MarginR, MarginV, Effect, Text',
-    'Comment: 0,0:00:01.00,0:00:03.00,OP English,,0,0,0,,{\\move(100,100,120,100)}POOF',
-    'Dialogue: 0,0:00:01.00,0:00:01.04,OP English,,0,0,0,,{\\pos(100,100)\\clip(m 1 1)}POOF',
-    'Dialogue: 0,0:00:01.04,0:00:01.08,OP English,,0,0,0,,{\\pos(100,100)\\clip(m 2 2)}POOF',
-    'Dialogue: 0,0:00:01.08,0:00:03.00,OP English,,0,0,0,,{\\pos(100,100)\\clip(m 3 3)}POOF',
-  ].join('\n');
-
-  assert.deepEqual(parseSubtitleCues(content, 'test.ass'), [
-    {
-      startTime: 1,
-      endTime: 3,
-      text: 'POOF',
-      source: 'canonical-ass',
-      animationStartTime: 1,
-      animationEndTime: 3,
-    },
-  ]);
-});
-
-test('parseSubtitleCues reconstructs a short positioned fragment without a lyric style name', () => {
-  const content = [
-    '[Events]',
-    'Format: Layer, Start, End, Style, Name, MarginL, MarginR, MarginV, Effect, Text',
-    'Dialogue: 0,0:00:01.00,0:00:03.00,Karaoke,,0,0,0,,{\\pos(100,100)\\t(0,100,\\fscx110)}Oh',
-    'Dialogue: 1,0:00:01.00,0:00:03.00,Karaoke,,0,0,0,,{\\pos(100,100)\\t(0,100,\\fscx110)}Oh',
-  ].join('\n');
-
-  assert.deepEqual(parseSubtitleCues(content, 'test.ass'), [
-    {
-      startTime: 1,
-      endTime: 3,
-      text: 'Oh',
-      source: 'reconstructed-ass',
-      animationStartTime: 1,
-      animationEndTime: 3,
-      assStyle: 'Karaoke',
-    },
-  ]);
-});
-
 test('parseSubtitleCues ignores timed comments without a matching animated dialogue cluster', () => {
  const content = [
    '[Events]',
@@ -8,27 +8,19 @@ import {
 } from './ass-text';
 import { hasAssAnimationEvidence, mergeDuplicateCues } from './subtitle-cue-dedup';

-export type AssCueLayout =
-  | { kind: 'positioned'; sourceOrder: number; y: number }
-  | { kind: 'fragment-grid'; sourceOrder: number }
-  | { kind: 'source-order'; sourceOrder: number };
-
 export interface SubtitleCue {
  startTime: number;
  endTime: number;
  text: string;
-  /** How a complete line was recovered from generated ASS animation events. */
-  source?: 'canonical-ass' | 'reconstructed-ass';
+  /** A complete authored line recovered from matching generated ASS animation events. */
+  source?: 'canonical-ass';
  /**
-   * Full span of the generated animation events a recovered cue replaced. Entrance and
-   * exit frames can run past canonical authored timing.
+   * Full span of the generated animation events a canonical cue replaced. Entrance and
+   * exit frames routinely run past the authored `startTime`/`endTime`, so live-text
+   * matching must use this envelope while display and history keep the authored timing.
   */
  animationStartTime?: number;
  animationEndTime?: number;
-  /** ASS style retained only for fragment-reconstructed lines. */
-  assStyle?: string;
-  /** Authored ASS ordering metadata used when flattening simultaneous positioned cues. */
-  assLayout?: AssCueLayout;
 }

 /**
@@ -37,7 +29,7 @@ export interface SubtitleCue {
 * override commands it carries, whether the `Effect` column was set -- to tell a karaoke
 * burst apart from two characters saying the same word in turn. None of it is meaningful
 * outside the parser, so the public API exposes only timing, text, and the optional
- * recovery marker used by live subtitle consumers.
+ * canonical-source marker used by live subtitle consumers.
 */
 export interface AnnotatedSubtitleCue extends SubtitleCue {
  /** Text exactly as authored, override blocks and all. */
@@ -83,55 +75,15 @@ function parseTimestamp(
 * line breaks, matching what mpv hands over for the same line played live. No layer
 * downstream decodes ASS again.
 */
-function decodeSubtitleCueText(text: string): string {
-  return assToPlainText(text, '\n').replace(HTML_SUBTITLE_TAG_PATTERN, '');
-}
-
 function sanitizeSubtitleCueText(text: string): string {
-  return decodeSubtitleCueText(text).trim();
-}
-
-function attachAssLayout<T extends SubtitleCue>(cue: T, assLayout: AssCueLayout | undefined): T {
-  if (assLayout) {
-    Object.defineProperty(cue, 'assLayout', { value: assLayout, enumerable: false });
-  }
-  return cue;
+  return assToPlainText(text, '\n').replace(HTML_SUBTITLE_TAG_PATTERN, '').trim();
 }

 function toPublicCues(cues: AnnotatedSubtitleCue[]): SubtitleCue[] {
-  return cues.map(
-    ({
-      startTime,
-      endTime,
-      text,
-      source,
-      animationStartTime,
-      animationEndTime,
-      style,
-      assLayout,
-    }) => {
-      const common = {
-        startTime,
-        endTime,
-        text,
-      };
-      if (source === 'reconstructed-ass') {
-        return attachAssLayout(
-          {
-            ...common,
-            source,
-            animationStartTime,
-            animationEndTime,
-            assStyle: style,
-          },
-          assLayout,
-        );
-      }
-      return attachAssLayout(
-        source ? { ...common, source, animationStartTime, animationEndTime } : common,
-        assLayout,
-      );
-    },
+  return cues.map(({ startTime, endTime, text, source, animationStartTime, animationEndTime }) =>
+    source
+      ? { startTime, endTime, text, source, animationStartTime, animationEndTime }
+      : { startTime, endTime, text },
  );
 }

@@ -207,11 +159,6 @@ const MIN_CANONICAL_ANIMATION_EVENTS = 3;
 // A tiny animated fragment can itself be composed from still smaller glyph events. It is
 // not enough evidence that the fragment represents an authored line boundary.
 const MIN_CANONICAL_DIALOGUE_TEXT_LENGTH = 4;
-const MIN_FRAGMENT_LINE_EVENTS = 8;
-const MIN_FRAGMENT_LINE_PARTS = 4;
-const MAX_FRAGMENT_MEDIAN_LENGTH = 4;
-const MAX_FRAGMENT_LINE_TIMING_VARIANCE_SECONDS = 2;
-const MAX_FRAGMENT_LINE_VERTICAL_SPAN = 48;

 function parseAssTimestamp(raw: string): number | null {
  const match = ASS_TIMING_PATTERN.exec(raw.trim());
@@ -349,240 +296,6 @@ function isRepeatedFragmentCopy(
  );
 }

-function hasRelaxedAssFragmentEvidence(events: readonly AnnotatedSubtitleCue[]): boolean {
-  if (events.length < 2 || !events.every((event) => fragmentPlacementAnchors(event).size > 0)) {
-    return false;
-  }
-
-  const latestStart = events.reduce(
-    (latest, event) => Math.max(latest, event.startTime),
-    -Infinity,
-  );
-  const earliestEnd = events.reduce(
-    (earliest, event) => Math.min(earliest, event.endTime),
-    Infinity,
-  );
-  if (latestStart >= earliestEnd) {
-    return false;
-  }
-
-  const first = events[0]!;
-  const hasChangingOverrides = events.some(
-    (event) => event.overrideSignature !== first.overrideSignature,
-  );
-  const hasPositionedLayerCopy = events.some((event, index) =>
-    events
-      .slice(0, index)
-      .some(
-        (previous) =>
-          compactCueMatchText(previous) === compactCueMatchText(event) &&
-          isRepeatedFragmentCopy(previous, event),
-      ),
-  );
-  return hasChangingOverrides || hasPositionedLayerCopy;
-}
-
-interface AssFragmentPart {
-  cue: AnnotatedSubtitleCue;
-  text: string;
-}
-
-function reconstructedAssFragmentLayout(
-  parts: readonly AssFragmentPart[],
-  owner: AnnotatedSubtitleCue,
-): AssCueLayout | undefined {
-  let positionedPartCount = 0;
-  let minimumY = Infinity;
-  let maximumY = -Infinity;
-  for (const part of parts) {
-    const layout = part.cue.assLayout;
-    if (layout?.kind !== 'positioned') continue;
-    positionedPartCount += 1;
-    minimumY = Math.min(minimumY, layout.y);
-    maximumY = Math.max(maximumY, layout.y);
-  }
-
-  if (
-    positionedPartCount >= MIN_FRAGMENT_LINE_PARTS &&
-    maximumY - minimumY > MAX_FRAGMENT_LINE_VERTICAL_SPAN
-  ) {
-    return { kind: 'fragment-grid', sourceOrder: owner.order };
-  }
-  return owner.assLayout;
-}
-
-interface AssFragmentTimingCluster {
-  events: AnnotatedSubtitleCue[];
-  minStartTime: number;
-  maxStartTime: number;
-  minEndTime: number;
-  maxEndTime: number;
-}
-
-function addToFragmentTimingCluster(
-  cluster: AssFragmentTimingCluster,
-  cue: AnnotatedSubtitleCue,
-): void {
-  cluster.events.push(cue);
-  cluster.minStartTime = Math.min(cluster.minStartTime, cue.startTime);
-  cluster.maxStartTime = Math.max(cluster.maxStartTime, cue.startTime);
-  cluster.minEndTime = Math.min(cluster.minEndTime, cue.endTime);
-  cluster.maxEndTime = Math.max(cluster.maxEndTime, cue.endTime);
-}
-
-function fragmentTimingDistance(
-  cluster: AssFragmentTimingCluster,
-  cue: AnnotatedSubtitleCue,
-): number {
-  const nextMinStart = Math.min(cluster.minStartTime, cue.startTime);
-  const nextMaxStart = Math.max(cluster.maxStartTime, cue.startTime);
-  const nextMinEnd = Math.min(cluster.minEndTime, cue.endTime);
-  const nextMaxEnd = Math.max(cluster.maxEndTime, cue.endTime);
-  if (
-    nextMaxStart - nextMinStart > MAX_FRAGMENT_LINE_TIMING_VARIANCE_SECONDS ||
-    nextMaxEnd - nextMinEnd > MAX_FRAGMENT_LINE_TIMING_VARIANCE_SECONDS
-  ) {
-    return Infinity;
-  }
-  return (
-    Math.abs(cue.startTime - (cluster.minStartTime + cluster.maxStartTime) / 2) +
-    Math.abs(cue.endTime - (cluster.minEndTime + cluster.maxEndTime) / 2)
-  );
-}
-
-function clusterAssFragmentEvents(
-  events: readonly AnnotatedSubtitleCue[],
-): AssFragmentTimingCluster[] {
-  const clusters: AssFragmentTimingCluster[] = [];
-  for (const cue of events) {
-    let nearest: AssFragmentTimingCluster | null = null;
-    let nearestDistance = Infinity;
-    for (const cluster of clusters) {
-      const distance = fragmentTimingDistance(cluster, cue);
-      if (distance < nearestDistance) {
-        nearest = cluster;
-        nearestDistance = distance;
-      }
-    }
-    if (nearest) {
-      addToFragmentTimingCluster(nearest, cue);
-    } else {
-      clusters.push({
-        events: [cue],
-        minStartTime: cue.startTime,
-        maxStartTime: cue.startTime,
-        minEndTime: cue.endTime,
-        maxEndTime: cue.endTime,
-      });
-    }
-  }
-  return clusters;
-}
-
-function decodeSingleAssFragment(cue: AnnotatedSubtitleCue): string | null {
-  const visibleLines = decodeSubtitleCueText(cue.rawText)
-    .split('\n')
-    .filter((line) => line.trim().length > 0);
-  return visibleLines.length === 1 ? visibleLines[0]! : null;
-}
-
-function reconstructAssFragmentLine(
-  events: readonly AnnotatedSubtitleCue[],
-): AnnotatedSubtitleCue | null {
-  const hasRelaxedEvidence = hasRelaxedAssFragmentEvidence(events);
-  const minimumEvents = hasRelaxedEvidence ? 2 : MIN_FRAGMENT_LINE_EVENTS;
-  if (events.length < minimumEvents || !hasAssAnimationEvidence(events)) {
-    return null;
-  }
-
-  const parts: AssFragmentPart[] = [];
-  for (const cue of events) {
-    const text = decodeSingleAssFragment(cue);
-    if (text === null) {
-      return null;
-    }
-    const compactText = compactAssMatchText(text);
-    const isLayerCopy = parts.some(
-      (part) =>
-        compactAssMatchText(part.text) === compactText && isRepeatedFragmentCopy(part.cue, cue),
-    );
-    if (!isLayerCopy) {
-      parts.push({ cue, text });
-    }
-  }
-
-  const minimumParts = hasRelaxedEvidence ? 1 : MIN_FRAGMENT_LINE_PARTS;
-  if (parts.length < minimumParts || (!hasRelaxedEvidence && parts.length === events.length)) {
-    return null;
-  }
-  const lengths = parts
-    .map((part) => compactAssMatchText(part.text).length)
-    .sort((left, right) => left - right);
-  if ((lengths[Math.floor(lengths.length / 2)] ?? Infinity) > MAX_FRAGMENT_MEDIAN_LENGTH) {
-    return null;
-  }
-
-  const text = parts
-    .map((part) => part.text)
-    .join('')
-    .trim();
-  if (!text) {
-    return null;
-  }
-  const owner = parts[0]!.cue;
-  const animationStartTime = earliestStartTime(events);
-  const animationEndTime = latestEndTime(events);
-  return {
-    ...owner,
-    startTime: animationStartTime,
-    endTime: animationEndTime,
-    text,
-    rawText: text,
-    source: 'reconstructed-ass',
-    animationStartTime,
-    animationEndTime,
-    assLayout: reconstructedAssFragmentLayout(parts, owner),
-    overrides: [],
-    overrideSignature: '',
-  };
-}
-
-function recoverFragmentOnlyAssLines(dialogue: AnnotatedSubtitleCue[]): AnnotatedSubtitleCue[] {
-  const groups = new Map<string, AnnotatedSubtitleCue[]>();
-  for (const cue of dialogue) {
-    if (cue.source !== undefined) {
-      continue;
-    }
-    const key = assEventGroupKey(cue);
-    const group = groups.get(key);
-    if (group) {
-      group.push(cue);
-    } else {
-      groups.set(key, [cue]);
-    }
-  }
-
-  const recovered: AnnotatedSubtitleCue[] = [];
-  const suppressed = new Set<AnnotatedSubtitleCue>();
-  for (const events of groups.values()) {
-    for (const cluster of clusterAssFragmentEvents(events)) {
-      const line = reconstructAssFragmentLine(cluster.events);
-      if (!line) {
-        continue;
-      }
-      recovered.push(line);
-      cluster.events.forEach((event) => suppressed.add(event));
-    }
-  }
-  if (recovered.length === 0) {
-    return dialogue;
-  }
-  return [...dialogue.filter((cue) => !suppressed.has(cue)), ...recovered].sort(
-    (left, right) =>
-      left.startTime - right.startTime || left.endTime - right.endTime || left.order - right.order,
-  );
-}
-
 function groupConsecutiveAssFragments(events: readonly AnnotatedSubtitleCue[]): FragmentGroup[] {
  const groups: FragmentGroup[] = [];
  for (const event of events) {
@@ -794,37 +507,6 @@ function recoverCanonicalAssEvents({
  );
 }

-function parseAssCoordinate(value: string | undefined): number | null {
-  if (!value?.trim()) return null;
-  const coordinate = Number(value.trim());
-  return Number.isFinite(coordinate) ? coordinate : null;
-}
-
-function buildAssCueLayout(
-  overrides: readonly AssOverrideCommand[],
-  sourceOrder: number,
-): AssCueLayout {
-  let y: number | null = null;
-  for (const command of overrides) {
-    if (command.animated) continue;
-    const name = command.name.toLowerCase();
-    const args = command.args.split(',');
-    if (name === 'pos') {
-      y = parseAssCoordinate(args[1]) ?? y;
-      continue;
-    }
-    if (name !== 'move') continue;
-    const startY = parseAssCoordinate(args[1]);
-    const endY = parseAssCoordinate(args[3]);
-    if (startY !== null && endY !== null) {
-      y = (startY + endY) / 2;
-    }
-  }
-  return y === null
-    ? { kind: 'source-order', sourceOrder }
-    : { kind: 'positioned', sourceOrder, y };
-}
-
 function parseAnnotatedAssEvents(content: string): ParsedAssEvents {
  const cues: AnnotatedSubtitleCue[] = [];
  const comments: AnnotatedSubtitleCue[] = [];
@@ -933,7 +615,6 @@ function parseAnnotatedAssEvents(content: string): ParsedAssEvents {
      overrides,
      overrideSignature: assOverrideSignature(overrides),
      order: eventOrder,
-      assLayout: buildAssCueLayout(overrides, eventOrder),
    };
    eventOrder += 1;
    if (eventPrefix === ASS_COMMENT_PREFIX) {
@@ -947,7 +628,7 @@ function parseAnnotatedAssEvents(content: string): ParsedAssEvents {
 }

 function parseAnnotatedAssCues(content: string): AnnotatedSubtitleCue[] {
-  return recoverFragmentOnlyAssLines(recoverCanonicalAssEvents(parseAnnotatedAssEvents(content)));
+  return recoverCanonicalAssEvents(parseAnnotatedAssEvents(content));
 }

 export function parseAssCues(content: string): SubtitleCue[] {
@@ -606,3 +606,93 @@ test('configureEarlyAppPaths pins userData to canonical SubMiner config dir', ()
  assert.equal(userDataPath, '/tmp/xdg/SubMiner');
  assert.deepEqual(calls, ['name:SubMiner', 'path:userData:/tmp/xdg/SubMiner']);
 });
+
+test('configureEarlyAppPaths isolates development runs from the production profile', () => {
+  const calls: string[] = [];
+
+  const userDataPath = configureEarlyAppPaths(
+    {
+      setName: (name) => calls.push(`name:${name}`),
+      setPath: (key, value) => calls.push(`path:${key}:${value}`),
+    },
+    {
+      platform: 'linux',
+      homeDir: '/home/tester',
+      xdgConfigHome: '/tmp/xdg',
+      existsSync: () => false,
+      argv: ['electron', '.', '--start', '--dev'],
+      env: {},
+    },
+  );
+
+  assert.equal(userDataPath, '/tmp/xdg/SubMiner-dev');
+  assert.deepEqual(calls, ['name:SubMiner', 'path:userData:/tmp/xdg/SubMiner-dev']);
+});
+
+test('configureEarlyAppPaths ignores development flags forwarded to mpv', () => {
+  for (const forwardedFlag of ['--dev', '--debug']) {
+    let selectedPath = '';
+    const userDataPath = configureEarlyAppPaths(
+      {
+        setName: () => {},
+        setPath: (_key, value) => {
+          selectedPath = value;
+        },
+      },
+      {
+        platform: 'linux',
+        homeDir: '/home/tester',
+        xdgConfigHome: '/tmp/xdg',
+        existsSync: () => false,
+        argv: ['electron', '.', '--launch-mpv', forwardedFlag],
+        env: {},
+      },
+    );
+
+    assert.equal(userDataPath, '/tmp/xdg/SubMiner');
+    assert.equal(selectedPath, '/tmp/xdg/SubMiner');
+  }
+});
+
+test('configureEarlyAppPaths uses the supplied environment for config discovery', () => {
+  const paths: string[] = [];
+
+  const userDataPath = configureEarlyAppPaths(
+    {
+      setName: () => {},
+      setPath: (_key, value) => paths.push(value),
+    },
+    {
+      platform: 'linux',
+      homeDir: '/home/tester',
+      existsSync: () => false,
+      argv: ['electron', '.', '--start'],
+      env: { XDG_CONFIG_HOME: '/tmp/injected-xdg' },
+    },
+  );
+
+  assert.equal(userDataPath, '/tmp/injected-xdg/SubMiner');
+  assert.deepEqual(paths, ['/tmp/injected-xdg/SubMiner']);
+});
+
+test('configureEarlyAppPaths allows an explicit production-profile development run', () => {
+  const paths: string[] = [];
+
+  const userDataPath = configureEarlyAppPaths(
+    {
+      setName: () => {},
+      setPath: (_key, value) => paths.push(value),
+    },
+    {
+      platform: 'win32',
+      appDataDir: 'C:\\Users\\tester\\AppData\\Roaming',
+      homeDir: 'C:\\Users\\tester',
+      existsSync: () => false,
+      argv: ['electron.exe', '.', '--debug'],
+      env: { SUBMINER_USE_PRODUCTION_PROFILE: '1' },
+    },
+  );
+
+  assert.equal(userDataPath, 'C:\\Users\\tester\\AppData\\Roaming\\SubMiner');
+  assert.deepEqual(paths, ['C:\\Users\\tester\\AppData\\Roaming\\SubMiner']);
+});
@@ -1,5 +1,6 @@
 import fs from 'node:fs';
 import os from 'node:os';
+import path from 'node:path';
 import { spawn } from 'node:child_process';
 import { CliArgs, hasExplicitCommand, parseArgs, shouldStartApp } from './cli/args';
 import { resolveConfigDir } from './config/path-resolution';
@@ -14,6 +15,8 @@ const TRANSPORTED_APP_ARGC_ENV = 'SUBMINER_APP_ARGC';
 const TRANSPORTED_APP_ARG_PREFIX = 'SUBMINER_APP_ARG_';
 const MAX_TRANSPORTED_APP_ARGS = 256;
 const APP_NAME = 'SubMiner';
+const DEVELOPMENT_APP_NAME = 'SubMiner-dev';
+export const USE_PRODUCTION_PROFILE_ENV = 'SUBMINER_USE_PRODUCTION_PROFILE';
 const DEFAULT_APP_CONTROL_HANDOFF_TIMEOUT_MS = 500;
 const MACOS_APP_CONTROL_HANDOFF_TIMEOUT_MS = 3000;
 const MPV_LONG_OPTIONS_WITH_SEPARATE_VALUES = new Set([
@@ -53,6 +56,8 @@ type EarlyAppPathOptions = {
  xdgConfigHome?: string;
  homeDir?: string;
  existsSync?: (candidate: string) => boolean;
+  argv?: string[];
+  env?: NodeJS.ProcessEnv;
 };

 function removeLsfgLayer(env: NodeJS.ProcessEnv): void {
@@ -252,13 +257,25 @@ export function normalizeStartupArgv(argv: string[], env: NodeJS.ProcessEnv): st
 }

 export function configureEarlyAppPaths(app: EarlyAppLike, options?: EarlyAppPathOptions): string {
-  const userDataPath = resolveConfigDir({
-    platform: options?.platform ?? process.platform,
-    appDataDir: options?.appDataDir ?? process.env.APPDATA,
-    xdgConfigHome: options?.xdgConfigHome ?? process.env.XDG_CONFIG_HOME,
+  const platform = options?.platform ?? process.platform;
+  const env = options?.env ?? process.env;
+  const configDir = resolveConfigDir({
+    platform,
+    appDataDir: options?.appDataDir ?? env.APPDATA,
+    xdgConfigHome: options?.xdgConfigHome ?? env.XDG_CONFIG_HOME,
    homeDir: options?.homeDir ?? os.homedir(),
    existsSync: options?.existsSync ?? fs.existsSync,
  });
+  const argv = options?.argv ?? process.argv;
+  const launchMpvIndex = argv.indexOf('--launch-mpv');
+  const appArgv = launchMpvIndex === -1 ? argv : argv.slice(0, launchMpvIndex);
+  const useDevelopmentProfile =
+    (appArgv.includes('--dev') || appArgv.includes('--debug')) &&
+    env[USE_PRODUCTION_PROFILE_ENV] !== '1';
+  const platformPath = platform === 'win32' ? path.win32 : path.posix;
+  const userDataPath = useDevelopmentProfile
+    ? platformPath.join(platformPath.dirname(configDir), DEVELOPMENT_APP_NAME)
+    : configDir;

  app.setName(APP_NAME);
  app.setPath('userData', userDataPath);
@@ -22,7 +22,10 @@ import {
  shouldHandleStatsDaemonCommandAtEntry,
  spawnDetachedApp,
 } from './main-entry-runtime';
-import { requestSingleInstanceLockEarly } from './main/early-single-instance';
+import {
+  requestSingleInstanceLockEarly,
+  shouldBypassSingleInstanceLockForArgv,
+} from './main/early-single-instance';
 import { readConfiguredWindowsMpvLaunch } from './main-entry-launch-config';
 import { isAppControlServerAvailable, sendAppControlCommand } from './shared/app-control-client';
 import {
@@ -35,6 +38,7 @@ import { createWindowsMpvLaunchDeps, launchWindowsMpv } from './main/runtime/win
 import { runStatsDaemonControlFromProcess } from './stats-daemon-entry';
 import { handleSyncCliAtEntry } from './main/sync-cli';
 import { createFatalErrorReporter, registerFatalErrorHandlers } from './main/fatal-error';
+import { enforceElectronRuntimeGuard } from './main/electron-runtime-guard';
 import { buildMpvLoggingArgs } from './shared/mpv-logging-args';
 import {
  applyLogFileTogglesToEnv,
@@ -192,11 +196,25 @@ registerFatalErrorHandlers({
 });

 function startMainProcess(): void {
-  const gotSingleInstanceLock = requestSingleInstanceLockEarly(app);
+  // Normal launches serialize the runtime guard with the profile-scoped lock. Stats daemon
+  // commands keep their existing lock bypass when Electron runs in Node mode.
+  const gotSingleInstanceLock =
+    shouldBypassSingleInstanceLockForArgv(process.argv) || requestSingleInstanceLockEarly(app);
  if (!gotSingleInstanceLock) {
    app.exit(0);
    return;
  }
+
+  const runtimeGuard = enforceElectronRuntimeGuard({
+    electronVersion: process.versions.electron ?? '',
+    userDataPath,
+  });
+  if (!runtimeGuard.ok) {
+    console.error(runtimeGuard.details);
+    dialog.showErrorBox(runtimeGuard.title, runtimeGuard.details);
+    app.exit(1);
+    return;
+  }
  try {
    require('./main.js');
  } catch (error) {
@@ -36,6 +36,10 @@ import { openPlaylistBrowser as openPlaylistBrowserRuntime } from './main/runtim
 import { createAniSkipRuntime } from './main/runtime/aniskip-runtime';
 import { resolveAniSkipMetadataForFile } from './main/runtime/aniskip-metadata';
 import { createDiscordRpcClient } from './main/runtime/discord-rpc-client.js';
+import {
+  assertYomitanDictionaryMutationSafe,
+  observeYomitanDictionaryCount,
+} from './main/runtime/yomitan-dictionary-integrity';
 import { startAppControlServer } from './main/runtime/app-control-server';
 import { createEnsureBackgroundStatsServerHandler } from './main/runtime/background-stats-startup';
 import {
@@ -312,7 +316,6 @@ import {
  promoteSettingsWindowAboveOverlay,
  registerGlobalShortcuts as registerGlobalShortcutsCore,
  replayCurrentSubtitleRuntime,
-  resolveSanitizedSubtitleSeekCommand,
  resolveJellyfinPlaybackPlanRuntime,
  runStartupBootstrapRuntime,
  saveJellyfinSubtitleDelay,
@@ -765,6 +768,7 @@ type BootServices = MainBootServicesResult<
 const bootServices = createMainBootServices({
  platform: process.platform,
  argv: process.argv,
+  configDir: app.getPath('userData'),
  appDataDir: process.env.APPDATA,
  xdgConfigHome: process.env.XDG_CONFIG_HOME,
  homeDir: os.homedir(),
@@ -1433,6 +1437,10 @@ const firstRunSetupService = createFirstRunSetupService({
      error: (message, ...args) => logger.error(message, ...args),
      info: (message, ...args) => logger.info(message, ...args),
    });
+    const integrity = observeYomitanDictionaryCount(USER_DATA_PATH, dictionaries.length);
+    if (!integrity.safe) {
+      logger.error(`[dictionary:integrity] ${integrity.message}`);
+    }
    return dictionaries.length;
  },
  isExternalYomitanConfigured: () =>
@@ -1959,31 +1967,6 @@ let linuxVisibleOverlayOwnerBindingKey: string | null = null;
 let linuxVisibleOverlayWindowModeSwitchToken = 0;
 let subtitleSidebarRequestedOpen = false;
 const SEEK_THRESHOLD_SECONDS = 3;
-const EXPLICIT_SEEK_INTENT_TTL_MS = 2000;
-let explicitSeekIntentExpiresAtMs = 0;
-
-function isExplicitMpvSeekCommand(command: readonly (string | number)[]): boolean {
-  return command[0] === 'seek' || command[0] === 'sub-seek';
-}
-
-function sendRendererMpvCommand(rawCommand: (string | number)[]): void {
-  const command =
-    resolveSanitizedSubtitleSeekCommand(
-      rawCommand,
-      appState.activeParsedSubtitleCues,
-      appState.mpvClient?.currentTimePos ?? Number.NaN,
-    ) ?? rawCommand;
-  if (isExplicitMpvSeekCommand(command)) {
-    explicitSeekIntentExpiresAtMs = Date.now() + EXPLICIT_SEEK_INTENT_TTL_MS;
-  }
-  sendMpvCommandRuntime(appState.mpvClient, command);
-}
-
-function consumeExplicitSeekIntent(): boolean {
-  const pending = explicitSeekIntentExpiresAtMs >= Date.now();
-  explicitSeekIntentExpiresAtMs = 0;
-  return pending;
-}

 const autoplaySubtitlePrimingRuntime = createAutoplaySubtitlePrimingRuntime({
  getCurrentMediaPath: () => appState.currentMediaPath,
@@ -2549,10 +2532,12 @@ const characterDictionaryAutoSyncRuntime = createCharacterDictionaryAutoSyncRunt
    ),
  getYomitanDictionaryInfo: async () => {
    await ensureYomitanExtensionLoaded();
-    return await getYomitanDictionaryInfo(getYomitanParserRuntimeDeps(), {
+    const dictionaries = await getYomitanDictionaryInfo(getYomitanParserRuntimeDeps(), {
      error: (message, ...args) => logger.error(message, ...args),
      info: (message, ...args) => logger.info(message, ...args),
    });
+    assertYomitanDictionaryMutationSafe(USER_DATA_PATH, dictionaries.length);
+    return dictionaries;
  },
  importYomitanDictionary: async (zipPath) => {
    if (yomitanProfilePolicy.isExternalReadOnlyMode()) {
@@ -2649,12 +2634,6 @@ const characterDictionaryAutoSyncRuntime = createCharacterDictionaryAutoSyncRunt
 const characterDictionaryImageLookup = createCharacterDictionaryImageLookup({
  userDataPath: USER_DATA_PATH,
  getCurrentMediaId: () => characterDictionaryAutoSyncRuntime.getCurrentMediaId(),
-  onIndexReady: () => refreshCurrentSubtitleAnnotations(),
-  onIndexReadyError: (error) =>
-    logger.warn(
-      'Failed to refresh subtitle annotations after character portrait index became ready.',
-      error,
-    ),
 });

 // Lets the Yomitan scan runtime skip name lookups at positions where no
@@ -4079,7 +4058,7 @@ const recordTrackedCardsMined = (count: number, noteIds?: number[]): void => {
  ensureImmersionTrackerStarted();
  appState.immersionTracker?.recordCardsMined(count, noteIds);
 };
-function refreshCurrentSubtitleAnnotations(): void {
+const refreshCurrentSubtitleAfterKnownWordUpdate = (): void => {
  const hasCurrentSubtitle = appState.currentSubText.trim().length > 0;
  if (hasCurrentSubtitle) {
    subtitlePrefetchService?.pause();
@@ -4090,7 +4069,7 @@ function refreshCurrentSubtitleAnnotations(): void {
    // Idle controller: no settle is coming to release the pause above.
    subtitlePrefetchService?.resume();
  }
-}
+};
 let hasAttemptedImmersionTrackerStartup = false;
 const ensureImmersionTrackerStarted = (): void => {
  if (hasAttemptedImmersionTrackerStartup || appState.immersionTracker) {
@@ -4606,7 +4585,6 @@ const {
    reportJellyfinRemoteProgress: (forceImmediate) => {
      void reportJellyfinRemoteProgress(forceImmediate);
    },
-    consumeExplicitSeek: () => consumeExplicitSeekIntent(),
    onTimePosUpdate: (time) => {
      const delta = time - lastObservedTimePos;
      if (subtitlePrefetchService && (delta > SEEK_THRESHOLD_SECONDS || delta < 0)) {
@@ -5114,7 +5092,9 @@ function initializeOverlayRuntime(): void {
    overlayModalRuntime.primeModalWindow();
  }
  appState.ankiIntegration?.setRecordCardsMinedCallback(recordTrackedCardsMined);
-  appState.ankiIntegration?.setKnownWordCacheUpdatedCallback(refreshCurrentSubtitleAnnotations);
+  appState.ankiIntegration?.setKnownWordCacheUpdatedCallback(
+    refreshCurrentSubtitleAfterKnownWordUpdate,
+  );
  appState.ankiIntegration?.setSubtitleMiningContextConsumer(consumePendingSubtitleMiningContext);
  syncOverlayMpvSubtitleSuppression();
 }
@@ -5512,7 +5492,8 @@ const { registerIpcRuntimeHandlers } = composeIpcRuntimeHandlers({
    showPlaybackFeedback: (text: string) => showConfiguredPlaybackFeedback(text),
    replayCurrentSubtitle: () => replayCurrentSubtitleRuntime(appState.mpvClient),
    playNextSubtitle: () => playNextSubtitleRuntime(appState.mpvClient),
-    sendMpvCommand: (rawCommand: (string | number)[]) => sendRendererMpvCommand(rawCommand),
+    sendMpvCommand: (rawCommand: (string | number)[]) =>
+      sendMpvCommandRuntime(appState.mpvClient, rawCommand),
    getMpvClient: () => appState.mpvClient,
    isMpvConnected: () => Boolean(appState.mpvClient && appState.mpvClient.connected),
    hasRuntimeOptionsManager: () => appState.runtimeOptionsManager !== null,
@@ -5906,7 +5887,7 @@ const { registerIpcRuntimeHandlers } = composeIpcRuntimeHandlers({
        appState.ankiIntegration = integration;
        appState.ankiIntegration?.setRecordCardsMinedCallback(recordTrackedCardsMined);
        appState.ankiIntegration?.setKnownWordCacheUpdatedCallback(
-          refreshCurrentSubtitleAnnotations,
+          refreshCurrentSubtitleAfterKnownWordUpdate,
        );
        appState.ankiIntegration?.setSubtitleMiningContextConsumer(
          consumePendingSubtitleMiningContext,
@@ -138,3 +138,56 @@ test('createMainBootServices builds boot-phase service bundle', () => {
  assert.deepEqual(calls, ['mkdir:/tmp/subminer-config', 'exit:7']);
  assert.equal(setPathValue, '/tmp/subminer-config');
 });
+
+test('createMainBootServices honors the profile selected by the early entrypoint', () => {
+  const services = createMainBootServices({
+    platform: 'linux',
+    argv: ['electron', '.', '--dev'],
+    configDir: '/tmp/SubMiner-dev',
+    appDataDir: undefined,
+    xdgConfigHome: undefined,
+    homeDir: '/home/tester',
+    defaultMpvLogFile: '/tmp/default.log',
+    envMpvLog: undefined,
+    defaultTexthookerPort: 5174,
+    getDefaultSocketPath: () => '/tmp/subminer.sock',
+    resolveConfigDir: () => {
+      throw new Error('early profile should be authoritative');
+    },
+    existsSync: () => false,
+    mkdirSync: () => {},
+    joinPath: (...parts) => parts.join('/'),
+    app: {
+      setPath: () => {},
+      quit: () => {},
+      exit: () => {},
+      on: () => ({}),
+      whenReady: async () => {},
+    },
+    shouldBypassSingleInstanceLock: () => false,
+    requestSingleInstanceLockEarly: () => true,
+    registerSecondInstanceHandlerEarly: () => {},
+    onConfigStartupParseError: () => {},
+    createConfigService: (configDir) => ({ configDir }),
+    createAnilistTokenStore: (targetPath) => ({ targetPath }),
+    createJellyfinTokenStore: (targetPath) => ({ targetPath }),
+    createAnilistUpdateQueue: (targetPath) => ({ targetPath }),
+    createSubtitleWebSocket: (payloadMode) => ({ payloadMode }),
+    createLogger: () => ({ warn: () => {}, info: () => {}, error: () => {} }),
+    createMainRuntimeRegistry: () => ({}),
+    createOverlayManager: () => ({ getMainWindow: () => null, getModalWindow: () => null }),
+    createOverlayModalInputState: () => ({
+      getModalInputExclusive: () => false,
+      handleModalInputStateChange: () => {},
+    }),
+    createOverlayContentMeasurementStore: () => ({}),
+    getSyncOverlayShortcutsForModal: () => () => {},
+    getSyncOverlayVisibilityForModal: () => () => {},
+    createOverlayModalRuntime: () => ({}),
+    createAppState: (input) => input,
+  });
+
+  assert.equal(services.configDir, '/tmp/SubMiner-dev');
+  assert.equal(services.userDataPath, '/tmp/SubMiner-dev');
+  assert.deepEqual(services.configService, { configDir: '/tmp/SubMiner-dev' });
+});
@@ -31,6 +31,7 @@ export interface MainBootServicesParams<
 > {
  platform: NodeJS.Platform;
  argv: string[];
+  configDir?: string;
  appDataDir: string | undefined;
  xdgConfigHome: string | undefined;
  homeDir: string;
@@ -174,13 +175,15 @@ export function createMainBootServices<
  TAppState,
  TAppLifecycleApp
 > {
-  const configDir = params.resolveConfigDir({
-    platform: params.platform,
-    appDataDir: params.appDataDir,
-    xdgConfigHome: params.xdgConfigHome,
-    homeDir: params.homeDir,
-    existsSync: params.existsSync,
-  });
+  const configDir =
+    params.configDir ??
+    params.resolveConfigDir({
+      platform: params.platform,
+      appDataDir: params.appDataDir,
+      xdgConfigHome: params.xdgConfigHome,
+      homeDir: params.homeDir,
+      existsSync: params.existsSync,
+    });
  const userDataPath = configDir;
  const defaultMpvLogPath = params.envMpvLog?.trim() || params.defaultMpvLogFile;
  const defaultImmersionDbPath = params.joinPath(userDataPath, 'immersion.sqlite');
@@ -450,7 +450,7 @@ export function createCharacterDictionaryRuntimeService(deps: CharacterDictionar
    }

    const nameSplitTokenizerAvailable = isNameSplitTokenizerAvailable();
-    const nameSplitResolution = nameSplitTokenizerAvailable
+    const resolvedNameSplits = nameSplitTokenizerAvailable
      ? await resolveJapaneseNameSplits(
          characters,
          deps.tokenizeJapaneseName!,
@@ -466,8 +466,8 @@ export function createCharacterDictionaryRuntimeService(deps: CharacterDictionar
          },
        )
      : undefined;
-    const resolvedNameSplits = nameSplitResolution?.splits;
-    const nameSplitSource = nameSplitResolution?.kind === 'complete' ? 'mecab' : 'heuristic';
+    const nameSplitSource =
+      resolvedNameSplits && resolvedNameSplits.size > 0 ? 'mecab' : 'heuristic';

    progress?.onGenerateProgress?.({
      mediaId,
@@ -198,66 +198,6 @@ test('createCharacterDictionaryImageLookup can scope duplicate names to the curr
  assert.equal(scoped.alt, 'Kazuma');
 });

-test('createCharacterDictionaryImageLookup reports and retries a failed index-ready callback', async () => {
-  const outputDir = makeTempDir();
-  const snapshot: CharacterDictionarySnapshot = {
-    formatVersion: CHARACTER_DICTIONARY_FORMAT_VERSION,
-    mediaId: 21858,
-    mediaTitle: 'Little Witch Academia',
-    entryCount: 1,
-    updatedAt: 1_700_000_000_000,
-    termEntries: [
-      [
-        'ダイアナ',
-        'だいあな',
-        'name primary',
-        '',
-        75,
-        [
-          {
-            type: 'structured-content',
-            content: {
-              tag: 'img',
-              path: 'img/m21858-c81709.png',
-              alt: 'ダイアナ・キャベンディッシュ',
-            },
-          },
-        ],
-        0,
-        '',
-      ],
-    ],
-    images: [{ path: 'img/m21858-c81709.png', dataBase64: PNG_1X1_BASE64 }],
-  };
-  await writeSnapshot(getSnapshotPath(outputDir, snapshot.mediaId), snapshot);
-  const callbackError = new Error('annotation refresh failed');
-  const reportingError = new Error('error reporter failed');
-  let readyCount = 0;
-  const reportedErrors: unknown[] = [];
-  const lookup = createCharacterDictionaryImageLookup({
-    outputDir,
-    onIndexReady: () => {
-      readyCount += 1;
-      if (readyCount === 1) {
-        throw callbackError;
-      }
-    },
-    onIndexReadyError: (error) => {
-      reportedErrors.push(error);
-      throw reportingError;
-    },
-  });
-
-  assert.equal(lookup.get('ダイアナ', snapshot.mediaId), null);
-  await waitForRefresh(() => (reportedErrors.length === 1 ? true : null));
-  assert.ok(lookup.get('ダイアナ', snapshot.mediaId));
-
-  assert.equal(readyCount, 2);
-  assert.deepEqual(reportedErrors, [callbackError]);
-  lookup.get('ダイアナ', snapshot.mediaId);
-  assert.equal(readyCount, 2);
-});
-
 test('createCharacterDictionaryImageLookup does not fall back globally on scoped miss', async () => {
  const outputDir = makeTempDir();
  const snapshot: CharacterDictionarySnapshot = {
@@ -218,8 +218,6 @@ export function createCharacterDictionaryImageLookup(deps: {
  userDataPath?: string;
  outputDir?: string;
  getCurrentMediaId?: () => number | null | undefined;
-  onIndexReady?: () => void;
-  onIndexReadyError?: (error: unknown) => void;
 }): {
  get: (term: string, mediaId?: number | null) => CharacterNameImage | null;
  invalidate: () => void;
@@ -231,24 +229,6 @@ export function createCharacterDictionaryImageLookup(deps: {
  let index = new Map<string, CharacterNameImage>();
  let indexByMediaId = new Map<number, Map<string, CharacterNameImage>>();
  let refreshInFlight = false;
-  let indexReadyDeliveryPending = false;
-
-  function deliverIndexReadyIfPending(): void {
-    if (!indexReadyDeliveryPending || !deps.onIndexReady) {
-      return;
-    }
-    indexReadyDeliveryPending = false;
-    try {
-      deps.onIndexReady();
-    } catch (error) {
-      indexReadyDeliveryPending = true;
-      try {
-        deps.onIndexReadyError?.(error);
-      } catch {
-        // Error reporting must not reject the detached index refresh task.
-      }
-    }
-  }

  // Rebuilding means re-reading every cached snapshot (potentially GBs of JSON), which used to run
  // synchronously inside a lookup and froze the whole app right after a snapshot changed. Lookups
@@ -261,7 +241,6 @@ export function createCharacterDictionaryImageLookup(deps: {
      signature = '';
      return;
    }
-    deliverIndexReadyIfPending();
    const nextSignature = getSnapshotDirectorySignature(outputDir);
    if (nextSignature === signature || refreshInFlight) {
      return;
@@ -283,8 +262,6 @@ export function createCharacterDictionaryImageLookup(deps: {
        index = nextIndex;
        indexByMediaId = nextIndexByMediaId;
        signature = nextSignature;
-        indexReadyDeliveryPending = deps.onIndexReady !== undefined;
-        deliverIndexReadyIfPending();
      } finally {
        refreshInFlight = false;
      }
@@ -43,8 +43,7 @@ test('resolveJapaneseNameSplits splits a single-kanji surname via person-name PO
    }),
  );

-  assert.equal(splits.kind, 'complete');
-  assert.deepEqual(splits.splits.get('東紫乃'), { family: '東', given: '紫乃' });
+  assert.deepEqual(splits.get('東紫乃'), { family: '東', given: '紫乃' });
 });

 test('resolveJapaneseNameSplits corrects a hint-length-misleading surname boundary', async () => {
@@ -65,8 +64,7 @@ test('resolveJapaneseNameSplits corrects a hint-length-misleading surname bounda
    }),
  );

-  assert.equal(splits.kind, 'complete');
-  assert.deepEqual(splits.splits.get('渡辺真奈美'), { family: '渡辺', given: '真奈美' });
+  assert.deepEqual(splits.get('渡辺真奈美'), { family: '渡辺', given: '真奈美' });
 });

 test('resolveJapaneseNameSplits falls back to hint readings when POS tags are generic', async () => {
@@ -87,8 +85,7 @@ test('resolveJapaneseNameSplits falls back to hint readings when POS tags are ge
    }),
  );

-  assert.equal(splits.kind, 'complete');
-  assert.deepEqual(splits.splits.get('鈴木みゆ'), { family: '鈴木', given: 'みゆ' });
+  assert.deepEqual(splits.get('鈴木みゆ'), { family: '鈴木', given: 'みゆ' });
 });

 test('resolveJapaneseNameSplits skips names whose tokens do not reconstruct the name', async () => {
@@ -99,8 +96,7 @@ test('resolveJapaneseNameSplits skips names whose tokens do not reconstruct the
    }),
  );

-  assert.equal(splits.kind, 'complete');
-  assert.equal(splits.splits.size, 0);
+  assert.equal(splits.size, 0);
 });

 test('resolveJapaneseNameSplits skips ambiguous or untagged segmentations', async () => {
@@ -121,8 +117,7 @@ test('resolveJapaneseNameSplits skips ambiguous or untagged segmentations', asyn
    }),
  );

-  assert.equal(splits.kind, 'complete');
-  assert.equal(splits.splits.size, 0);
+  assert.equal(splits.size, 0);
 });

 test('resolveJapaneseNameSplits survives tokenizer failures', async () => {
@@ -135,8 +130,7 @@ test('resolveJapaneseNameSplits survives tokenizer failures', async () => {
    (message) => warnings.push(message),
  );

-  assert.equal(splits.kind, 'incomplete');
-  assert.equal(splits.splits.size, 0);
+  assert.equal(splits.size, 0);
  assert.equal(warnings.length, 1);
  assert.match(warnings[0]!, /mecab unavailable/);
 });
@@ -7,10 +7,6 @@ import type {
  ResolvedNameSplit,
 } from './types';

-export type JapaneseNameSplitResolution =
-  | { kind: 'complete'; splits: Map<string, ResolvedNameSplit> }
-  | { kind: 'incomplete'; splits: Map<string, ResolvedNameSplit> };
-
 const NAME_SEPARATOR_PATTERN = /[\s　・･·•]/;

 function joinSurfaces(tokens: NameSplitToken[]): string {
@@ -91,9 +87,8 @@ export async function resolveJapaneseNameSplits(
  tokenize: NameSplitTokenizer,
  logWarn?: (message: string) => void,
  onCharacterResolved?: (completed: number, total: number) => void,
-): Promise<JapaneseNameSplitResolution> {
+): Promise<Map<string, ResolvedNameSplit>> {
  const splits = new Map<string, ResolvedNameSplit>();
-  let tokenizerFailed = false;
  let resolvedCharacters = 0;
  for (const character of characters) {
    const familyHintReading = buildReadingFromHint(character.lastNameHint?.trim() || '');
@@ -104,17 +99,12 @@ export async function resolveJapaneseNameSplits(
      try {
        tokens = await tokenize(name);
      } catch (err) {
-        tokenizerFailed = true;
        logWarn?.(
          `[dictionary] name split tokenization failed for "${name}": ${(err as Error).message}`,
        );
        continue;
      }
-      if (!tokens) {
-        tokenizerFailed = true;
-        continue;
-      }
-      if (tokens.length < 2 || joinSurfaces(tokens) !== name) continue;
+      if (!tokens || tokens.length < 2 || joinSurfaces(tokens) !== name) continue;
      const splitIndex =
        splitIndexFromPersonNamePos(tokens) ??
        splitIndexFromHintReadings(tokens, familyHintReading, givenHintReading);
@@ -128,5 +118,5 @@ export async function resolveJapaneseNameSplits(
    resolvedCharacters += 1;
    onCharacterResolved?.(resolvedCharacters, characters.length);
  }
-  return tokenizerFailed ? { kind: 'incomplete', splits } : { kind: 'complete', splits };
+  return splits;
 }
@@ -7,7 +7,7 @@ import test from 'node:test';
 import { createCharacterDictionaryRuntimeService } from '../character-dictionary-runtime';
 import { getSnapshotPath, writeSnapshot } from './cache';
 import { CHARACTER_DICTIONARY_FORMAT_VERSION } from './constants';
-import type { CharacterDictionarySnapshot, NameSplitTokenizer } from './types';
+import type { CharacterDictionarySnapshot } from './types';

 const GRAPHQL_URL = 'https://graphql.anilist.co';
 const PNG_1X1 = Buffer.from(
@@ -121,12 +121,7 @@ test('generateForCurrentMedia refreshes same-version snapshots missing images wh
  }
 });

-async function runNameSplitRefreshScenario(tokenizeJapaneseName: NameSplitTokenizer): Promise<{
-  characterPageRequests: number;
-  firstResultFromCache: boolean;
-  refreshedNameSplitSource: CharacterDictionarySnapshot['nameSplitSource'];
-  secondResultFromCache: boolean;
-}> {
+test('generateForCurrentMedia keeps failed MeCab name split refreshes retryable', async () => {
  const userDataPath = makeTempDir();
  const outputDir = path.join(userDataPath, 'character-dictionaries');
  await writeSnapshot(getSnapshotPath(outputDir, 130298), {
@@ -177,6 +172,7 @@ async function runNameSplitRefreshScenario(tokenizeJapaneseName: NameSplitTokeni
  }) as typeof globalThis.fetch;

  try {
+    let tokenizerCalls = 0;
    const runtime = createCharacterDictionaryRuntimeService({
      userDataPath,
      getCurrentMediaPath: () => '/tmp/eminence-s01e05.mkv',
@@ -189,54 +185,29 @@ async function runNameSplitRefreshScenario(tokenizeJapaneseName: NameSplitTokeni
        source: 'fallback',
      }),
      getNameMatchImagesEnabled: () => false,
-      tokenizeJapaneseName,
+      tokenizeJapaneseName: async () => {
+        tokenizerCalls += 1;
+        return null;
+      },
      getJapaneseNameTokenizerAvailable: () => true,
      now: () => 1_700_000_000_500,
    });

-    const firstResult = await runtime.generateForCurrentMedia();
+    const result = await runtime.generateForCurrentMedia();
    const refreshedSnapshot = JSON.parse(
      fs.readFileSync(getSnapshotPath(outputDir, 130298), 'utf8'),
    ) as CharacterDictionarySnapshot;
-    const secondResult = await runtime.generateForCurrentMedia();

-    return {
-      characterPageRequests,
-      firstResultFromCache: firstResult.fromCache,
-      refreshedNameSplitSource: refreshedSnapshot.nameSplitSource,
-      secondResultFromCache: secondResult.fromCache,
-    };
+    assert.equal(result.fromCache, false);
+    assert.equal(refreshedSnapshot.nameSplitSource, 'heuristic');
+
+    const retriedResult = await runtime.generateForCurrentMedia();
+    assert.equal(retriedResult.fromCache, false);
+    assert.equal(characterPageRequests, 2);
+    assert.equal(tokenizerCalls, 2);
  } finally {
    globalThis.fetch = originalFetch;
  }
-}
-
-test('generateForCurrentMedia keeps failed MeCab name split refreshes retryable', async () => {
-  let tokenizerCalls = 0;
-  const result = await runNameSplitRefreshScenario(async () => {
-    tokenizerCalls += 1;
-    return null;
-  });
-
-  assert.equal(result.firstResultFromCache, false);
-  assert.equal(result.refreshedNameSplitSource, 'heuristic');
-  assert.equal(result.secondResultFromCache, false);
-  assert.equal(result.characterPageRequests, 2);
-  assert.equal(tokenizerCalls, 2);
-});
-
-test('generateForCurrentMedia caches completed MeCab refreshes with no resolved splits', async () => {
-  let tokenizerCalls = 0;
-  const result = await runNameSplitRefreshScenario(async () => {
-    tokenizerCalls += 1;
-    return [];
-  });
-
-  assert.equal(result.firstResultFromCache, false);
-  assert.equal(result.refreshedNameSplitSource, 'mecab');
-  assert.equal(result.secondResultFromCache, true);
-  assert.equal(result.characterPageRequests, 1);
-  assert.equal(tokenizerCalls, 1);
 });

 test('generateForCurrentMedia keeps mecab-split snapshots when MeCab is available', async () => {
@@ -0,0 +1,142 @@
+import assert from 'node:assert/strict';
+import fs from 'node:fs';
+import os from 'node:os';
+import path from 'node:path';
+import test from 'node:test';
+import { enforceElectronRuntimeGuard, SUPPORTED_ELECTRON_MAJOR } from './electron-runtime-guard';
+
+function withTempDir(run: (directory: string) => void): void {
+  const directory = fs.mkdtempSync(path.join(os.tmpdir(), 'subminer-electron-guard-'));
+  try {
+    run(directory);
+  } finally {
+    fs.rmSync(directory, { recursive: true, force: true });
+  }
+}
+
+test('runtime guard major matches the pinned Electron dependency', () => {
+  const packageJson = JSON.parse(
+    fs.readFileSync(path.join(process.cwd(), 'package.json'), 'utf8'),
+  ) as { devDependencies: { electron: string } };
+
+  assert.equal(Number.parseInt(packageJson.devDependencies.electron.split('.', 1)[0]!, 10), 43);
+  assert.equal(SUPPORTED_ELECTRON_MAJOR, 43);
+});
+
+test('runtime guard records the supported Electron major', () => {
+  withTempDir((userDataPath) => {
+    const result = enforceElectronRuntimeGuard({
+      electronVersion: '43.4.1',
+      userDataPath,
+      supportedElectronMajor: 43,
+    });
+
+    assert.equal(result.ok, true);
+    assert.deepEqual(JSON.parse(fs.readFileSync(result.statePath, 'utf8')), {
+      highestElectronMajor: 43,
+      lastElectronVersion: '43.4.1',
+    });
+  });
+});
+
+test('runtime guard rejects a runtime outside the build major without writing state', () => {
+  withTempDir((userDataPath) => {
+    const result = enforceElectronRuntimeGuard({
+      electronVersion: '44.0.0',
+      userDataPath,
+      supportedElectronMajor: 43,
+    });
+
+    assert.equal(result.ok, false);
+    if (result.ok) return;
+    assert.equal(result.title, 'Unsupported Electron runtime');
+    assert.match(result.details, /requires Electron 43/);
+    assert.equal(fs.existsSync(result.statePath), false);
+  });
+});
+
+test('runtime guard rejects prerelease Electron versions without writing state', () => {
+  withTempDir((userDataPath) => {
+    const result = enforceElectronRuntimeGuard({
+      electronVersion: '43.4.1-beta.1',
+      userDataPath,
+      supportedElectronMajor: 43,
+    });
+
+    assert.equal(result.ok, false);
+    if (result.ok) return;
+    assert.equal(result.title, 'SubMiner could not verify Electron');
+    assert.equal(fs.existsSync(result.statePath), false);
+  });
+});
+
+test('runtime guard blocks a profile downgrade before rewriting its safety record', () => {
+  withTempDir((userDataPath) => {
+    const statePath = path.join(userDataPath, 'electron-runtime.json');
+    fs.writeFileSync(
+      statePath,
+      JSON.stringify({ highestElectronMajor: 44, lastElectronVersion: '44.1.0' }),
+      'utf8',
+    );
+
+    const result = enforceElectronRuntimeGuard({
+      electronVersion: '43.4.1',
+      userDataPath,
+      supportedElectronMajor: 43,
+    });
+
+    assert.equal(result.ok, false);
+    if (result.ok) return;
+    assert.equal(result.title, 'Electron downgrade blocked');
+    assert.match(result.details, /destroy Yomitan dictionaries/);
+    assert.equal(result.details.includes(statePath), true);
+    assert.deepEqual(JSON.parse(fs.readFileSync(statePath, 'utf8')), {
+      highestElectronMajor: 44,
+      lastElectronVersion: '44.1.0',
+    });
+  });
+});
+
+test('runtime guard blocks a downgrade within the supported Electron major', () => {
+  withTempDir((userDataPath) => {
+    const statePath = path.join(userDataPath, 'electron-runtime.json');
+    fs.writeFileSync(
+      statePath,
+      JSON.stringify({ highestElectronMajor: 43, lastElectronVersion: '43.4.1' }),
+      'utf8',
+    );
+
+    const result = enforceElectronRuntimeGuard({
+      electronVersion: '43.3.0',
+      userDataPath,
+      supportedElectronMajor: 43,
+    });
+
+    assert.equal(result.ok, false);
+    if (result.ok) return;
+    assert.equal(result.title, 'Electron downgrade blocked');
+    assert.equal(result.details.includes(statePath), true);
+    assert.deepEqual(JSON.parse(fs.readFileSync(statePath, 'utf8')), {
+      highestElectronMajor: 43,
+      lastElectronVersion: '43.4.1',
+    });
+  });
+});
+
+test('runtime guard fails closed when its safety record is malformed', () => {
+  withTempDir((userDataPath) => {
+    const statePath = path.join(userDataPath, 'electron-runtime.json');
+    fs.writeFileSync(statePath, '{}', 'utf8');
+
+    const result = enforceElectronRuntimeGuard({
+      electronVersion: '43.4.1',
+      userDataPath,
+      supportedElectronMajor: 43,
+    });
+
+    assert.equal(result.ok, false);
+    if (result.ok) return;
+    assert.equal(result.title, 'SubMiner profile safety check failed');
+    assert.match(result.details, /invalid format/);
+  });
+});
@@ -0,0 +1,171 @@
+import fs from 'node:fs';
+import path from 'node:path';
+import { writeTextFileAtomicallyDurable } from '../shared/fs-utils';
+
+export const SUPPORTED_ELECTRON_MAJOR = 43;
+const RUNTIME_STATE_FILE_NAME = 'electron-runtime.json';
+
+type ElectronRuntimeState = {
+  highestElectronMajor: number;
+  lastElectronVersion: string;
+};
+
+type ParsedElectronVersion = {
+  major: number;
+  minor: number;
+  patch: number;
+};
+
+type ValidatedElectronRuntimeState = {
+  state: ElectronRuntimeState;
+  version: ParsedElectronVersion;
+};
+
+export type ElectronRuntimeGuardResult =
+  | { ok: true; statePath: string }
+  | { ok: false; title: string; details: string; statePath: string };
+
+function parseElectronVersion(version: string): ParsedElectronVersion | null {
+  const match = /^(\d+)\.(\d+)\.(\d+)(?:\+[0-9A-Za-z.-]+)?$/.exec(version.trim());
+  if (!match) return null;
+
+  const major = Number.parseInt(match[1]!, 10);
+  const minor = Number.parseInt(match[2]!, 10);
+  const patch = Number.parseInt(match[3]!, 10);
+  if (![major, minor, patch].every((part) => Number.isSafeInteger(part) && part >= 0)) {
+    return null;
+  }
+  if (major === 0) return null;
+  return { major, minor, patch };
+}
+
+function compareElectronVersions(
+  left: ParsedElectronVersion,
+  right: ParsedElectronVersion,
+): number {
+  return left.major - right.major || left.minor - right.minor || left.patch - right.patch;
+}
+
+function readRuntimeState(statePath: string): ValidatedElectronRuntimeState | null {
+  if (!fs.existsSync(statePath)) return null;
+
+  const parsed = JSON.parse(fs.readFileSync(statePath, 'utf8')) as Partial<ElectronRuntimeState>;
+  const highestElectronMajor = parsed.highestElectronMajor;
+  const lastElectronVersion =
+    typeof parsed.lastElectronVersion === 'string'
+      ? parseElectronVersion(parsed.lastElectronVersion)
+      : null;
+  if (
+    typeof highestElectronMajor !== 'number' ||
+    !Number.isSafeInteger(highestElectronMajor) ||
+    highestElectronMajor <= 0 ||
+    lastElectronVersion === null
+  ) {
+    throw new Error('The runtime safety record has an invalid format.');
+  }
+
+  return {
+    state: {
+      highestElectronMajor,
+      lastElectronVersion: parsed.lastElectronVersion!,
+    },
+    version: lastElectronVersion,
+  };
+}
+
+function writeRuntimeState(statePath: string, state: ElectronRuntimeState): void {
+  writeTextFileAtomicallyDurable(statePath, `${JSON.stringify(state, null, 2)}\n`);
+}
+
+export function enforceElectronRuntimeGuard(options: {
+  electronVersion: string;
+  userDataPath: string;
+  supportedElectronMajor?: number;
+}): ElectronRuntimeGuardResult {
+  const supportedElectronMajor = options.supportedElectronMajor ?? SUPPORTED_ELECTRON_MAJOR;
+  const statePath = path.join(options.userDataPath, RUNTIME_STATE_FILE_NAME);
+  const currentVersion = parseElectronVersion(options.electronVersion);
+
+  if (currentVersion === null) {
+    return {
+      ok: false,
+      title: 'SubMiner could not verify Electron',
+      details: `Electron reported an invalid version: ${JSON.stringify(options.electronVersion)}. SubMiner did not load Yomitan storage.`,
+      statePath,
+    };
+  }
+
+  if (currentVersion.major !== supportedElectronMajor) {
+    return {
+      ok: false,
+      title: 'Unsupported Electron runtime',
+      details: [
+        `This SubMiner build requires Electron ${supportedElectronMajor}.`,
+        `The current runtime is Electron ${options.electronVersion}.`,
+        '',
+        'Launch SubMiner through its packaged application or the repository package scripts. Yomitan storage was not loaded.',
+      ].join('\n'),
+      statePath,
+    };
+  }
+
+  let previousState: ValidatedElectronRuntimeState | null;
+  try {
+    previousState = readRuntimeState(statePath);
+  } catch (error) {
+    return {
+      ok: false,
+      title: 'SubMiner profile safety check failed',
+      details: [
+        `SubMiner could not read the runtime safety record at ${statePath}.`,
+        (error as Error).message,
+        '',
+        'Yomitan storage was not loaded. Repair or remove only this safety record after verifying the profile backup.',
+      ].join('\n'),
+      statePath,
+    };
+  }
+
+  if (
+    previousState &&
+    (currentVersion.major < previousState.state.highestElectronMajor ||
+      compareElectronVersions(currentVersion, previousState.version) < 0)
+  ) {
+    return {
+      ok: false,
+      title: 'Electron downgrade blocked',
+      details: [
+        `This profile was previously opened with Electron ${previousState.state.lastElectronVersion}.`,
+        `The current runtime is Electron ${options.electronVersion}.`,
+        `Runtime safety record: ${statePath}.`,
+        '',
+        'Opening Chromium storage with an older Electron version can destroy Yomitan dictionaries. Upgrade SubMiner before using this profile.',
+      ].join('\n'),
+      statePath,
+    };
+  }
+
+  try {
+    writeRuntimeState(statePath, {
+      highestElectronMajor: Math.max(
+        currentVersion.major,
+        previousState?.state.highestElectronMajor ?? 0,
+      ),
+      lastElectronVersion: options.electronVersion,
+    });
+  } catch (error) {
+    return {
+      ok: false,
+      title: 'SubMiner profile safety check failed',
+      details: [
+        `SubMiner could not update the runtime safety record at ${statePath}.`,
+        (error as Error).message,
+        '',
+        'Yomitan storage was not loaded.',
+      ].join('\n'),
+      statePath,
+    };
+  }
+
+  return { ok: true, statePath };
+}
@@ -482,10 +482,10 @@ test('Linux visible overlay recreation avoids display fallback before tracked ge
  assert.doesNotMatch(actionBlock, /setOverlayWindowBounds\(getCurrentOverlayGeometry\(\)\)/);
 });

-test('subtitle annotation updates invalidate prefetched tokenizations before refreshing current subtitle', () => {
+test('known-word updates invalidate prefetched tokenizations before refreshing current subtitle', () => {
  const source = readMainSource();
  const actionBlock = source.match(
-    /function refreshCurrentSubtitleAnnotations\(\): void \{(?<body>[\s\S]*?)\n\}/,
+    /const refreshCurrentSubtitleAfterKnownWordUpdate = \(\): void => \{(?<body>[\s\S]*?)\n\};/,
  )?.groups?.body;

  assert.ok(actionBlock);
@@ -503,20 +503,6 @@ test('subtitle annotation updates invalidate prefetched tokenizations before ref
  );
 });

-test('character portrait index readiness refreshes cached subtitle annotations', () => {
-  const source = readMainSource();
-  const lookupDeps = source.match(
-    /const characterDictionaryImageLookup = createCharacterDictionaryImageLookup\(\{(?<body>[\s\S]*?)\n\}\);/,
-  )?.groups?.body;
-
-  assert.ok(lookupDeps);
-  assert.match(lookupDeps, /onIndexReady: \(\) => refreshCurrentSubtitleAnnotations\(\),/);
-  assert.match(
-    lookupDeps,
-    /onIndexReadyError: \(error\) =>[\s\S]*?logger\.warn\([\s\S]*?character portrait index became ready\.[\s\S]*?error,/,
-  );
-});
-
 test('subtitle processing controller resumes prefetch on settle, not on its emits', () => {
  const source = readMainSource();
  const depsBlock = source.match(
@@ -1,6 +1,5 @@
 import assert from 'node:assert/strict';
 import test from 'node:test';
-import { parseSubtitleCues } from '../../core/services/subtitle-cue-parser';
 import { createSubtitleProcessingController } from '../../core/services/subtitle-processing-controller';
 import type { SubtitleData } from '../../types';
 import {
@@ -212,69 +211,6 @@ test('primeCurrentSubtitleForAutoplay emits raw first paint on cache miss before
  ]);
 });

-test('parsed cues replace a duplicate raw autoplay subtitle that was already primed', async () => {
-  const rawText = 'ジグザグな道を抜け\nジグザグな道を抜け';
-  const correctedText = 'ジグザグな道を抜け';
-  const mediaPath = '/media/video.mkv';
-  let currentSubText = '';
-  const emitted: string[] = [];
-  const client = {
-    connected: true,
-    currentVideoPath: mediaPath,
-    currentTimePos: 90,
-    currentSubText: rawText,
-    requestProperty: async (name: string) => {
-      if (name === 'sub-text') return rawText;
-      if (name === 'time-pos') return 90;
-      return null;
-    },
-  };
-  const cues = parseSubtitleCues(
-    [
-      '[Events]',
-      'Format: Layer, Start, End, Style, Name, MarginL, MarginR, MarginV, Effect, Text',
-      `Dialogue: 1,0:01:29.00,0:01:32.00,EDJP,,0,0,0,,${correctedText}`,
-      `Dialogue: 0,0:01:29.00,0:01:32.00,EDJP,,0,0,0,,${correctedText}`,
-    ].join('\n'),
-    'startup-ending.ass',
-  );
-  let activeCues = cues.slice(0, 0);
-  const runtime = createAutoplaySubtitlePrimingRuntime({
-    getCurrentMediaPath: () => mediaPath,
-    getMpvClient: () => client,
-    setCurrentSubText: (text) => {
-      currentSubText = text;
-    },
-    getCurrentSubText: () => currentSubText,
-    getCurrentSubtitleData: () => null,
-    getActiveParsedSubtitleCues: () => activeCues,
-    setActiveParsedSubtitleMediaPath: () => {},
-    subtitleProcessingController: {
-      consumeCachedSubtitle: () => null,
-      onSubtitleChange: () => true,
-      refreshCurrentSubtitle: () => true,
-      notePlainSubtitleEmitted: () => {},
-    },
-    emitSubtitlePayload: (payload) => emitted.push(payload.text),
-    getSubtitlePrefetchService: () => null,
-    getLastObservedTimePos: () => 90,
-    getVisibleOverlayVisible: () => true,
-    emitSecondarySubtitle: () => {},
-    initSubtitlePrefetch: async () => {},
-    refreshSubtitlePrefetchFromActiveTrack: async () => {},
-    logDebug: () => {},
-  });
-
-  await runtime.primeCurrentSubtitleForAutoplay(mediaPath);
-  assert.equal(currentSubText, rawText);
-
-  activeCues = cues;
-  await runtime.primeAutoplaySubtitleFromParsedCues(mediaPath, cues);
-
-  assert.equal(currentSubText, correctedText);
-  assert.deepEqual(emitted, [rawText, correctedText]);
-});
-
 // Driven by the real processing controller rather than a stub: the failure this
 // covers is a disagreement between the priming path and the controller's own
 // staleness rules, which a hand-written stub cannot reproduce.
@@ -12,7 +12,6 @@ type AutoplaySubtitlePrimingMpvClient = {
  requestProperty: (name: string) => Promise<unknown>;
  currentVideoPath?: string;
  currentTimePos?: number;
-  currentSubText?: string;
  currentSecondarySubText?: string;
  setCurrentSecondarySubText?: (text: string) => void;
 };
@@ -108,19 +107,11 @@ export function createAutoplaySubtitlePrimingRuntime(deps: AutoplaySubtitlePrimi
    autoplaySubtitlePrimedMediaPath = null;
  }

-  function emitAutoplayPrimedSubtitle(
-    mediaPath: string,
-    text: string,
-    options: { replaceExisting?: boolean } = {},
-  ): boolean {
+  function emitAutoplayPrimedSubtitle(mediaPath: string, text: string): boolean {
    if (!text.trim() || !isCurrentAutoplayMediaPath(mediaPath)) {
      return false;
    }
-    if (autoplaySubtitlePrimedMediaPath === mediaPath) {
-      if (!options.replaceExisting || deps.getCurrentSubText() === text) {
-        return false;
-      }
-    } else if (!markAutoplaySubtitlePrimeConsumed(mediaPath)) {
+    if (!markAutoplaySubtitlePrimeConsumed(mediaPath)) {
      return false;
    }

@@ -261,7 +252,11 @@ export function createAutoplaySubtitlePrimingRuntime(deps: AutoplaySubtitlePrimi
    mediaPath: string,
    cues: SubtitleCue[],
  ): Promise<void> {
-    if (cues.length === 0 || !isCurrentAutoplayMediaPath(mediaPath)) {
+    if (
+      cues.length === 0 ||
+      autoplaySubtitlePrimedMediaPath === mediaPath ||
+      !isCurrentAutoplayMediaPath(mediaPath)
+    ) {
      return;
    }

@@ -270,21 +265,16 @@ export function createAutoplaySubtitlePrimingRuntime(deps: AutoplaySubtitlePrimi
    const currentTimeSeconds = Number(
      timePosRaw ?? client?.currentTimePos ?? deps.getLastObservedTimePos() ?? 0,
    );
-    const resolvedTimeSeconds = Number.isFinite(currentTimeSeconds) ? currentTimeSeconds : 0;
    const cue = selectAutoplayStartupCue(
      cues,
-      resolvedTimeSeconds,
+      Number.isFinite(currentTimeSeconds) ? currentTimeSeconds : 0,
      AUTOPLAY_SUBTITLE_PRIME_LOOKAHEAD_SECONDS,
    );
-    const liveText = client?.currentSubText ?? '';
-    const text = liveText.trim()
-      ? resolvePrimarySubtitleText({ liveText, currentTimeSec: resolvedTimeSeconds, cues })
-      : (cue?.text ?? '');
-    if (!text) {
+    if (!cue) {
      return;
    }

-    emitAutoplayPrimedSubtitle(mediaPath, text, { replaceExisting: true });
+    emitAutoplayPrimedSubtitle(mediaPath, cue.text);
  }

  function clearScheduledSubtitlePrefetchRefresh(): void {
@@ -8,18 +8,6 @@ import {
  resolveManagedLinuxRuntimePluginPaths,
 } from './linux-runtime-plugin-assets';

-const THUMBNAILER_RELATIVE_PATH = path.join(
-  'thumbnailers',
-  'subminer-ffmpegthumbnailer.thumbnailer',
-);
-
-function writeThumbnailer(rootDir: string, content = '[Thumbnailer Entry]\n'): string {
-  const thumbnailerPath = path.join(rootDir, THUMBNAILER_RELATIVE_PATH);
-  fs.mkdirSync(path.dirname(thumbnailerPath), { recursive: true });
-  fs.writeFileSync(thumbnailerPath, content);
-  return thumbnailerPath;
-}
-
 async function withTempDir<T>(fn: (dir: string) => Promise<T> | T): Promise<T> {
  const dir = fs.mkdtempSync(path.join(os.tmpdir(), 'subminer-linux-plugin-assets-test-'));
  try {
@@ -60,7 +48,6 @@ test('resolveManagedLinuxRuntimePluginPaths resolves XDG data target paths', ()
    pluginEntrypointPath: '/tmp/xdg-data/SubMiner/plugin/subminer/main.lua',
    pluginConfigPath: '/tmp/xdg-data/SubMiner/plugin/subminer.conf',
    themePath: '/tmp/xdg-data/SubMiner/themes/subminer.rasi',
-    thumbnailerPath: '/tmp/xdg-data/SubMiner/thumbnailers/subminer-ffmpegthumbnailer.thumbnailer',
  });
 });

@@ -92,7 +79,6 @@ test('ensureLinuxRuntimePluginAssets installs managed plugin dir, config, and ro
  await withTempDir(async (tempDir) => {
    const sourceRoot = path.join(tempDir, 'source', 'plugin');
    const themeSourcePath = path.join(tempDir, 'source', 'assets', 'themes', 'subminer.rasi');
-    const thumbnailerSourcePath = writeThumbnailer(path.join(tempDir, 'source', 'assets'));
    const targetRoot = path.join(tempDir, 'xdg-data', 'SubMiner', 'plugin');
    fs.mkdirSync(path.join(sourceRoot, 'subminer'), { recursive: true });
    fs.mkdirSync(path.dirname(themeSourcePath), { recursive: true });
@@ -108,7 +94,6 @@ test('ensureLinuxRuntimePluginAssets installs managed plugin dir, config, and ro
        pluginDirSource: path.join(sourceRoot, 'subminer'),
        pluginConfigSource: path.join(sourceRoot, 'subminer.conf'),
        themeSourcePath,
-        thumbnailerSourcePath,
      }),
    });

@@ -132,19 +117,6 @@ test('ensureLinuxRuntimePluginAssets installs managed plugin dir, config, and ro
      ),
      '/* theme */\n',
    );
-    assert.equal(
-      fs.readFileSync(
-        path.join(
-          tempDir,
-          'xdg-data',
-          'SubMiner',
-          'thumbnailers',
-          'subminer-ffmpegthumbnailer.thumbnailer',
-        ),
-        'utf8',
-      ),
-      '[Thumbnailer Entry]\n',
-    );
  });
 });

@@ -152,7 +124,6 @@ test('ensureLinuxRuntimePluginAssets installs managed theme when plugin assets a
  await withTempDir(async (tempDir) => {
    const sourceRoot = path.join(tempDir, 'source', 'plugin');
    const themeSourcePath = path.join(tempDir, 'source', 'assets', 'themes', 'subminer.rasi');
-    const thumbnailerSourcePath = writeThumbnailer(path.join(tempDir, 'source', 'assets'));
    const xdgDataHome = path.join(tempDir, 'xdg-data');
    const targetRoot = path.join(xdgDataHome, 'SubMiner', 'plugin');
    fs.mkdirSync(path.join(sourceRoot, 'subminer'), { recursive: true });
@@ -172,7 +143,6 @@ test('ensureLinuxRuntimePluginAssets installs managed theme when plugin assets a
        pluginDirSource: path.join(sourceRoot, 'subminer'),
        pluginConfigSource: path.join(sourceRoot, 'subminer.conf'),
        themeSourcePath,
-        thumbnailerSourcePath,
      }),
    });

@@ -199,7 +169,6 @@ test('ensureLinuxRuntimePluginAssets installs managed theme when plugin assets a
 test('ensureLinuxRuntimePluginAssets installs managed theme without resolving plugin sources when plugin assets already exist', async () => {
  await withTempDir(async (tempDir) => {
    const themeSourcePath = path.join(tempDir, 'source', 'assets', 'themes', 'subminer.rasi');
-    const thumbnailerSourcePath = writeThumbnailer(path.join(tempDir, 'source', 'assets'));
    const xdgDataHome = path.join(tempDir, 'xdg-data');
    const targetRoot = path.join(xdgDataHome, 'SubMiner', 'plugin');
    fs.mkdirSync(path.dirname(themeSourcePath), { recursive: true });
@@ -214,7 +183,6 @@ test('ensureLinuxRuntimePluginAssets installs managed theme without resolving pl
      xdgDataHome,
      resolveBundledAssets: () => ({
        themeSourcePath,
-        thumbnailerSourcePath,
      }),
    });

@@ -282,7 +250,6 @@ test('ensureLinuxRuntimePluginAssets installs managed plugin assets without reso
      path.join(xdgDataHome, 'SubMiner', 'themes', 'subminer.rasi'),
      '/* existing theme */\n',
    );
-    const thumbnailerSourcePath = writeThumbnailer(path.join(tempDir, 'source', 'assets'));

    const result = await ensureLinuxRuntimePluginAssets({
      platform: 'linux',
@@ -291,7 +258,6 @@ test('ensureLinuxRuntimePluginAssets installs managed plugin assets without reso
      resolveBundledAssets: () => ({
        pluginDirSource: path.join(sourceRoot, 'subminer'),
        pluginConfigSource: path.join(sourceRoot, 'subminer.conf'),
-        thumbnailerSourcePath,
      }),
    });

@@ -366,7 +332,6 @@ test('ensureLinuxRuntimePluginAssets returns already-present when managed assets
      path.join(xdgDataHome, 'SubMiner', 'themes', 'subminer.rasi'),
      '/* theme */\n',
    );
-    writeThumbnailer(path.join(xdgDataHome, 'SubMiner'));

    const result = await ensureLinuxRuntimePluginAssets({
      platform: 'linux',
@@ -404,7 +369,6 @@ test('ensureLinuxRuntimePluginAssets leaves no final target tree on failed insta
  await withTempDir(async (tempDir) => {
    const sourceRoot = path.join(tempDir, 'source', 'plugin');
    const themeSourcePath = path.join(tempDir, 'source', 'assets', 'themes', 'subminer.rasi');
-    const thumbnailerSourcePath = writeThumbnailer(path.join(tempDir, 'source', 'assets'));
    const xdgDataHome = path.join(tempDir, 'xdg-data');
    const targetRoot = path.join(xdgDataHome, 'SubMiner', 'plugin');
    fs.mkdirSync(path.join(sourceRoot, 'subminer'), { recursive: true });
@@ -421,7 +385,6 @@ test('ensureLinuxRuntimePluginAssets leaves no final target tree on failed insta
        pluginDirSource: path.join(sourceRoot, 'subminer'),
        pluginConfigSource: path.join(sourceRoot, 'subminer.conf'),
        themeSourcePath,
-        thumbnailerSourcePath,
      }),
      copyFile: async () => {
        throw new Error('copy failed');
@@ -10,7 +10,6 @@ export interface ManagedLinuxRuntimePluginPaths {
  pluginEntrypointPath: string;
  pluginConfigPath: string;
  themePath: string;
-  thumbnailerPath: string;
 }

 export interface EnsureLinuxRuntimePluginAssetsResult {
@@ -24,7 +23,6 @@ interface RuntimePluginAssetSources {
  pluginDirSource?: string;
  pluginConfigSource?: string;
  themeSourcePath?: string;
-  thumbnailerSourcePath?: string;
 }

 interface RuntimePluginDirentLike {
@@ -74,11 +72,6 @@ export function resolveManagedLinuxRuntimePluginPaths(options: {
    pluginEntrypointPath: pathModule.join(pluginDir, 'main.lua'),
    pluginConfigPath: pathModule.join(rootDir, 'subminer.conf'),
    themePath: pathModule.join(dataDir, 'themes', 'subminer.rasi'),
-    thumbnailerPath: pathModule.join(
-      dataDir,
-      'thumbnailers',
-      'subminer-ffmpegthumbnailer.thumbnailer',
-    ),
  };
 }

@@ -102,12 +95,11 @@ async function copyDirectoryRecursive(
  }
 }

-function resolveBundledAssetPath(options: {
+function resolveBundledThemePath(options: {
  dirname: string;
  appPath: string;
  resourcesPath: string;
  existsSync: (candidate: string) => boolean;
-  relativePath: string;
 }): string | null {
  const roots = [
    path.join(options.resourcesPath, 'assets'),
@@ -119,7 +111,7 @@ function resolveBundledAssetPath(options: {
  ];

  for (const root of roots) {
-    const candidate = path.join(root, options.relativePath);
+    const candidate = path.join(root, 'themes', 'subminer.rasi');
    if (options.existsSync(candidate)) return candidate;
  }

@@ -137,25 +129,16 @@ function resolveBundledAssetsDefault(
    existsSync,
  });

-  const themeSourcePath = resolveBundledAssetPath({
+  const themeSourcePath = resolveBundledThemePath({
    dirname: __dirname,
    appPath: process.execPath,
    resourcesPath,
    existsSync,
-    relativePath: path.join('themes', 'subminer.rasi'),
-  });
-  const thumbnailerSourcePath = resolveBundledAssetPath({
-    dirname: __dirname,
-    appPath: process.execPath,
-    resourcesPath,
-    existsSync,
-    relativePath: path.join('thumbnailers', 'subminer-ffmpegthumbnailer.thumbnailer'),
  });

  return {
    ...(pluginAssets ?? {}),
    ...(themeSourcePath ? { themeSourcePath } : {}),
-    ...(thumbnailerSourcePath ? { thumbnailerSourcePath } : {}),
  };
 }

@@ -195,8 +178,7 @@ export async function ensureLinuxRuntimePluginAssets(
  const pluginAssetsExist =
    existsSync(managedPaths.pluginEntrypointPath) && existsSync(managedPaths.pluginConfigPath);
  const themeExists = existsSync(managedPaths.themePath);
-  const thumbnailerExists = existsSync(managedPaths.thumbnailerPath);
-  if (pluginAssetsExist && themeExists && thumbnailerExists) {
+  if (pluginAssetsExist && themeExists) {
    return {
      ok: true,
      status: 'already-present',
@@ -211,7 +193,6 @@ export async function ensureLinuxRuntimePluginAssets(

  const shouldInstallPluginAssets = !pluginAssetsExist;
  const shouldInstallTheme = !themeExists;
-  const shouldInstallThumbnailer = !thumbnailerExists;
  if (
    shouldInstallPluginAssets &&
    (!bundledAssets.pluginDirSource || !bundledAssets.pluginConfigSource)
@@ -229,13 +210,6 @@ export async function ensureLinuxRuntimePluginAssets(
      error: 'Bundled Linux runtime theme asset was not found.',
    };
  }
-  if (shouldInstallThumbnailer && !bundledAssets.thumbnailerSourcePath) {
-    return {
-      ok: false,
-      status: 'failed',
-      error: 'Bundled Linux rofi thumbnailer asset was not found.',
-    };
-  }

  const stagingSuffix = `${process.pid}-${Date.now()}`;
  const stagedPluginDir = pathModule.join(managedPaths.rootDir, `.subminer-stage-${stagingSuffix}`);
@@ -247,14 +221,9 @@ export async function ensureLinuxRuntimePluginAssets(
    pathModule.dirname(managedPaths.themePath),
    `.subminer.rasi-stage-${stagingSuffix}`,
  );
-  const stagedThumbnailerPath = pathModule.join(
-    pathModule.dirname(managedPaths.thumbnailerPath),
-    `.subminer-ffmpegthumbnailer.thumbnailer-stage-${stagingSuffix}`,
-  );
  let pluginDirInstalled = false;
  let pluginConfigInstalled = false;
  let themeInstalled = false;
-  let thumbnailerInstalled = false;

  try {
    if (shouldInstallPluginAssets) {
@@ -280,14 +249,6 @@ export async function ensureLinuxRuntimePluginAssets(
      await mkdir(pathModule.dirname(managedPaths.themePath), { recursive: true });
      await copyFile(themeSourcePath, stagedThemePath);
    }
-    if (shouldInstallThumbnailer) {
-      const thumbnailerSourcePath = bundledAssets.thumbnailerSourcePath;
-      if (!thumbnailerSourcePath) {
-        throw new Error('Bundled Linux rofi thumbnailer asset was not found.');
-      }
-      await mkdir(pathModule.dirname(managedPaths.thumbnailerPath), { recursive: true });
-      await copyFile(thumbnailerSourcePath, stagedThumbnailerPath);
-    }
    if (shouldInstallPluginAssets) {
      await rm(managedPaths.pluginDir, { recursive: true, force: true });
      await rm(managedPaths.pluginConfigPath, { force: true });
@@ -301,11 +262,6 @@ export async function ensureLinuxRuntimePluginAssets(
      await rename(stagedThemePath, managedPaths.themePath);
      themeInstalled = true;
    }
-    if (shouldInstallThumbnailer) {
-      await rm(managedPaths.thumbnailerPath, { force: true });
-      await rename(stagedThumbnailerPath, managedPaths.thumbnailerPath);
-      thumbnailerInstalled = true;
-    }

    return {
      ok: true,
@@ -322,13 +278,9 @@ export async function ensureLinuxRuntimePluginAssets(
    if (themeInstalled) {
      await rm(managedPaths.themePath, { force: true }).catch(() => {});
    }
-    if (thumbnailerInstalled) {
-      await rm(managedPaths.thumbnailerPath, { force: true }).catch(() => {});
-    }
    await rm(stagedPluginDir, { recursive: true, force: true }).catch(() => {});
    await rm(stagedPluginConfigPath, { force: true }).catch(() => {});
    await rm(stagedThemePath, { force: true }).catch(() => {});
-    await rm(stagedThumbnailerPath, { force: true }).catch(() => {});
    return {
      ok: false,
      status: 'failed',
@@ -358,30 +358,6 @@ test('time-pos handler forces Jellyfin progress when mpv position jumps', () =>
  ]);
 });

-test('time-pos handler treats an explicit short jump as a seek', () => {
-  const updateKinds: string[] = [];
-  let explicitSeekPending = false;
-  const timeHandler = createHandleMpvTimePosChangeHandler({
-    recordPlaybackPosition: () => {},
-    reportJellyfinRemoteProgress: () => {},
-    refreshDiscordPresence: () => {},
-    maybeRunAnilistPostWatchUpdate: async () => {},
-    consumeExplicitSeek: () => {
-      const pending = explicitSeekPending;
-      explicitSeekPending = false;
-      return pending;
-    },
-    onTimePosUpdate: (_time, kind) => updateKinds.push(kind),
-  });
-
-  timeHandler({ time: 10 });
-  explicitSeekPending = true;
-  timeHandler({ time: 11.5 });
-  timeHandler({ time: 11.6 });
-
-  assert.deepEqual(updateKinds, ['initial', 'seek', 'playback']);
-});
-
 test('time-pos handler passes fresh playback time to AniList post-watch', async () => {
  const watchedSeconds: unknown[] = [];
  const timeHandler = createHandleMpvTimePosChangeHandler({
@@ -4,8 +4,6 @@ type AnilistPostWatchRunOptions = {
  watchedSeconds?: number;
 };

-type TimePosUpdateKind = 'initial' | 'playback' | 'seek';
-
 /** Jump size that marks a time-pos change as a seek rather than normal playback. */
 export const SEEK_LIKE_TIME_DELTA_SECONDS = 2.5;

@@ -140,20 +138,12 @@ export function createHandleMpvTimePosChangeHandler(deps: {
  refreshDiscordPresence: () => void;
  maybeRunAnilistPostWatchUpdate?: (options?: AnilistPostWatchRunOptions) => Promise<void>;
  logError?: (message: string, error: unknown) => void;
-  onTimePosUpdate?: (time: number, kind: TimePosUpdateKind) => void;
-  consumeExplicitSeek?: () => boolean;
+  onTimePosUpdate?: (time: number) => void;
 }) {
  let lastObservedTime: number | null = null;

  return ({ time }: { time: number }): void => {
-    const explicitSeek = deps.consumeExplicitSeek?.() ?? false;
-    const updateKind: TimePosUpdateKind =
-      lastObservedTime === null
-        ? 'initial'
-        : explicitSeek || isSeekLikeTimeChange(lastObservedTime, time)
-          ? 'seek'
-          : 'playback';
-    const forceImmediate = updateKind === 'seek';
+    const forceImmediate = isSeekLikeTimeChange(lastObservedTime, time);
    if (Number.isFinite(time)) {
      lastObservedTime = time;
    }
@@ -163,7 +153,7 @@ export function createHandleMpvTimePosChangeHandler(deps: {
    void deps.maybeRunAnilistPostWatchUpdate?.({ watchedSeconds: time }).catch((error) => {
      deps.logError?.('AniList post-watch update failed unexpectedly', error);
    });
-    deps.onTimePosUpdate?.(time, updateKind);
+    deps.onTimePosUpdate?.(time);
  };
 }

@@ -1,23 +1,10 @@
 import assert from 'node:assert/strict';
 import test from 'node:test';
-import { parseSubtitleCues } from '../../core/services/subtitle-cue-parser';
 import { createBindMpvMainEventHandlersHandler } from './mpv-main-event-bindings';
-import { resolvePrimarySubtitleText } from './primary-subtitle-text';

 test('main mpv event binder wires callbacks through to runtime deps', () => {
  const handlers = new Map<string, (payload: unknown) => void>();
  const calls: string[] = [];
-  let currentTime = 0;
-  const seekLiveText = '少しだけ好きになる\n少しだけ好きになる';
-  const seekCues = parseSubtitleCues(
-    [
-      '[Events]',
-      'Format: Layer, Start, End, Style, Name, MarginL, MarginR, MarginV, Effect, Text',
-      'Dialogue: 1,0:01:29.00,0:01:32.00,EDJP,,0,0,0,,少しだけ好きになる',
-      'Dialogue: 0,0:01:29.00,0:01:32.00,EDJP,,0,0,0,,少しだけ好きになる',
-    ].join('\n'),
-    'seek-ending.ass',
-  );

  const bind = createBindMpvMainEventHandlersHandler({
    reportJellyfinRemoteStopped: () => calls.push('remote-stopped'),
@@ -40,9 +27,6 @@ test('main mpv event binder wires callbacks through to runtime deps', () => {
      calls.push(`post-watch:${options?.watchedSeconds ?? 'none'}`);
    },
    logSubtitleTimingError: () => calls.push('subtitle-error'),
-    resolveSubtitleText: (liveText) =>
-      resolvePrimarySubtitleText({ liveText, currentTimeSec: currentTime, cues: seekCues }),
-    getCurrentLiveSubtitleText: () => seekLiveText,
    setCurrentSubText: (text) => calls.push(`set-sub:${text}`),
    getImmediateSubtitlePayload: (text) => ({ text, tokens: [] }),
    broadcastSubtitle: (payload) => calls.push(`broadcast-sub:${payload.text}`),
@@ -76,9 +60,6 @@ test('main mpv event binder wires callbacks through to runtime deps', () => {
    recordMediaDuration: (duration) => calls.push(`duration:${duration}`),
    reportJellyfinRemoteProgress: (forceImmediate) =>
      calls.push(`progress:${forceImmediate ? 'force' : 'normal'}`),
-    onTimePosUpdate: (time) => {
-      currentTime = time;
-    },
    recordPauseState: (paused) => calls.push(`pause:${paused ? 'yes' : 'no'}`),

    updateSubtitleRenderMetrics: () => calls.push('subtitle-metrics'),
@@ -102,13 +83,7 @@ test('main mpv event binder wires callbacks through to runtime deps', () => {
  handlers.get('media-path-change')?.({ path: '' });
  handlers.get('media-title-change')?.({ title: 'Episode 1' });
  handlers.get('subtitle-timing')?.({ text: 'timed line', start: 899, end: 901 });
-  handlers.get('subtitle-change')?.({ text: seekLiveText });
-  handlers.get('time-pos-change')?.({ time: 90 });
-  assert.ok(calls.includes('set-sub:少しだけ好きになる'));
-
  handlers.get('time-pos-change')?.({ time: 2.5 });
-  handlers.get('subtitle-change')?.({ text: seekLiveText });
-  handlers.get('time-pos-change')?.({ time: 90 });
  handlers.get('pause-change')?.({ paused: true });

  assert.ok(calls.includes('set-sub:line'));
@@ -44,7 +44,6 @@ export function createBindMpvMainEventHandlersHandler(deps: {

  setCurrentSubText: (text: string) => void;
  resolveSubtitleText?: (text: string) => string;
-  getCurrentLiveSubtitleText?: () => string;
  getImmediateSubtitlePayload?: (text: string) => SubtitleData | null;
  emitImmediateSubtitle?: (payload: SubtitleData) => void;
  broadcastSubtitle: (payload: SubtitleData) => void;
@@ -79,7 +78,6 @@ export function createBindMpvMainEventHandlersHandler(deps: {
  recordMediaDuration: (durationSec: number) => void;
  reportJellyfinRemoteProgress: (forceImmediate: boolean) => void;
  onTimePosUpdate?: (time: number) => void;
-  consumeExplicitSeek?: () => boolean;
  onFullscreenChange?: (fullscreen: boolean) => void;
  recordPauseState: (paused: boolean) => void;

@@ -173,15 +171,7 @@ export function createBindMpvMainEventHandlersHandler(deps: {
      refreshDiscordPresence: () => deps.refreshDiscordPresence(),
      maybeRunAnilistPostWatchUpdate: (options) => deps.maybeRunAnilistPostWatchUpdate(options),
      logError: (message, error) => deps.logSubtitleTimingError(message, error),
-      consumeExplicitSeek: deps.consumeExplicitSeek,
-      onTimePosUpdate: (time, updateKind) => {
-        deps.onTimePosUpdate?.(time);
-        if (updateKind === 'playback') return;
-        const liveText = deps.getCurrentLiveSubtitleText?.();
-        if (liveText !== undefined) {
-          handleMpvSubtitleChange({ text: liveText });
-        }
-      },
+      onTimePosUpdate: (time) => deps.onTimePosUpdate?.(time),
    });
    const handleMpvPauseChange = createHandleMpvPauseChangeHandler({
      recordPauseState: (paused) => deps.recordPauseState(paused),
@@ -21,7 +21,6 @@ export function createBuildBindMpvMainEventHandlersMainDepsHandler(deps: {
    overlayRuntimeInitialized: boolean;
    mpvClient: {
      connected?: boolean;
-      currentSubText?: string;
      currentSecondarySubText?: string;
      currentTimePos?: number;
      requestProperty?: (name: string) => Promise<unknown>;
@@ -86,7 +85,6 @@ export function createBuildBindMpvMainEventHandlersMainDepsHandler(deps: {
  resetAnilistMediaGuessState: () => void;
  reportJellyfinRemoteProgress: (forceImmediate: boolean) => void;
  onTimePosUpdate?: (time: number) => void;
-  consumeExplicitSeek?: () => boolean;
  onFullscreenChange?: (fullscreen: boolean) => void;
  updateSubtitleRenderMetrics: (patch: Record<string, unknown>) => void;
  refreshDiscordPresence: () => void;
@@ -162,7 +160,6 @@ export function createBuildBindMpvMainEventHandlersMainDepsHandler(deps: {
        currentTimeSec: Number(deps.appState.mpvClient?.currentTimePos),
        cues: deps.appState.activeParsedSubtitleCues,
      }),
-    getCurrentLiveSubtitleText: () => deps.appState.mpvClient?.currentSubText ?? '',
    recordImmersionSubtitleLine: (text: string, start: number, end: number) => {
      deps.ensureImmersionTrackerInitialized();
      const tracker = deps.appState.immersionTracker;
@@ -335,7 +332,6 @@ export function createBuildBindMpvMainEventHandlersMainDepsHandler(deps: {
    },
    reportJellyfinRemoteProgress: (forceImmediate: boolean) =>
      deps.reportJellyfinRemoteProgress(forceImmediate),
-    consumeExplicitSeek: deps.consumeExplicitSeek,
    onTimePosUpdate: (time: number) => {
      // Timing history is a viewing log: after a real backward seek, a rewatched
      // canonical line should enter it again. Immersion stats keep their
@@ -64,30 +64,6 @@ test('resolvePrimarySubtitleText combines unique simultaneous parsed cues', () =
  );
 });

-test('resolvePrimarySubtitleText collapses whitespace variants of one ASS lyric', () => {
-  const ass = [
-    '[Events]',
-    'Format: Layer, Start, End, Style, Name, MarginL, MarginR, MarginV, Effect, Text',
-    'Dialogue: 2,0:00:01.00,0:00:03.00,EDJP,,0,0,0,,少しだけ好きになる',
-    'Dialogue: 1,0:00:01.00,0:00:03.00,EDJP,,0,0,0,,少しだけ\\h好きになる',
-    'Dialogue: 0,0:00:01.00,0:00:03.00,EDJP,,0,0,0,,少しだけ　好きになる',
-  ].join('\n');
-  const cues = parseSubtitleCues(ass, 'polar-opposites-s01e10.ass');
-
-  assert.deepEqual(
-    cues.map((cue) => cue.text),
-    ['少しだけ好きになる', '少しだけ 好きになる', '少しだけ　好きになる'],
-  );
-  assert.equal(
-    resolvePrimarySubtitleText({
-      liveText: ['少しだけ好きになる', '少しだけ 好きになる', '少しだけ　好きになる'].join('\n'),
-      currentTimeSec: 2,
-      cues,
-    }),
-    '少しだけ好きになる',
-  );
-});
-
 test('resolvePrimarySubtitleText tolerates stale time-pos at a parsed cue edge', () => {
  assert.equal(
    resolvePrimarySubtitleText({
@@ -208,20 +184,6 @@ test('resolvePrimarySubtitleText combines simultaneous canonical cues in source
  assert.equal(text, 'first\nsecond');
 });

-test('resolvePrimarySubtitleText collapses whitespace variants of a canonical lyric', () => {
-  assert.equal(
-    resolvePrimarySubtitleText({
-      liveText: '少しだけ好きになる\n少しだけ　好きになる',
-      currentTimeSec: 2,
-      cues: [
-        { startTime: 1, endTime: 3, text: '少しだけ好きになる', source: 'canonical-ass' },
-        { startTime: 1, endTime: 3, text: '少しだけ　好きになる', source: 'canonical-ass' },
-      ],
-    }),
-    '少しだけ好きになる',
-  );
-});
-
 test('resolveCanonicalPrimarySubtitle covers a nearby generated animation edge', () => {
  const cue = {
    startTime: 1.2,
@@ -25,7 +25,7 @@ function nearbyCanonicalCues(
  currentTimeSec: number,
 ): SubtitleCue[] {
  return (cues ?? []).filter((cue) => {
-    if (cue.source !== 'canonical-ass' && cue.source !== 'reconstructed-ass') {
+    if (cue.source !== 'canonical-ass') {
      return false;
    }
    const span = animationSpan(cue);
@@ -40,21 +40,6 @@ function compactWhitespace(text: string): string {
  return text.replace(/\s+/gu, '');
 }

-// ASS layers can encode the same visible spacing with ordinary, hard, or
-// ideographic spaces. Matching and emission must use the same identity or each
-// layer reappears as a copy.
-function uniqueCueTexts(cues: readonly SubtitleCue[]): string[] {
-  const texts: string[] = [];
-  const seen = new Set<string>();
-  for (const cue of cues) {
-    const compactText = compactWhitespace(cue.text);
-    if (seen.has(compactText)) continue;
-    seen.add(compactText);
-    texts.push(cue.text);
-  }
-  return texts;
-}
-
 function compactLineSegments(text: string): string[] {
  return text.split('\n').map(compactWhitespace).filter(Boolean);
 }
@@ -98,7 +83,14 @@ function resolveActiveParsedPrimarySubtitle(options: {
    return null;
  }

-  const texts = uniqueCueTexts(selected);
+  const texts: string[] = [];
+  const seen = new Set<string>();
+  for (const cue of selected) {
+    if (!seen.has(cue.text)) {
+      seen.add(cue.text);
+      texts.push(cue.text);
+    }
+  }
  return {
    text: texts.join('\n'),
    startTime: Math.min(...selected.map((cue) => cue.startTime)),
@@ -167,7 +159,14 @@ export function resolveCanonicalPrimarySubtitle(options: {
    return null;
  }

-  const texts = uniqueCueTexts(selected);
+  const texts: string[] = [];
+  const seen = new Set<string>();
+  for (const cue of selected) {
+    if (!seen.has(cue.text)) {
+      seen.add(cue.text);
+      texts.push(cue.text);
+    }
+  }
  return {
    text: texts.join('\n'),
    startTime: Math.min(...selected.map((cue) => cue.startTime)),
@@ -20,194 +20,6 @@ test('findActiveSubtitleText combines unique simultaneous parsed cues', () => {
  );
 });

-test('findActiveSubtitleText collapses whitespace variants of one ASS lyric', () => {
-  assert.equal(
-    findActiveSubtitleText(
-      [
-        { startTime: 1, endTime: 3, text: '少しだけ好きになる' },
-        { startTime: 1, endTime: 3, text: '少しだけ 好きになる' },
-        { startTime: 1, endTime: 3, text: '少しだけ　好きになる' },
-      ],
-      2,
-    ),
-    '少しだけ好きになる',
-  );
-});
-
-test('parsed secondary text collapses a positioned sign that repeats dialogue without punctuation', () => {
-  const ass = [
-    '[Events]',
-    'Format: Layer, Start, End, Style, Name, MarginL, MarginR, MarginV, Effect, Text',
-    'Dialogue: 10,0:03:58.49,0:04:00.34,GJM_Main_1080p,Nar,0,0,0,,{\\i1}A question veiled as an insult!',
-    'Dialogue: 1,0:03:58.59,0:04:00.34,iFanzSigns,,0,0,0,,{\\pos(960,75)}A question veiled as an insult',
-  ].join('\n');
-  const cues = parseSubtitleCues(ass, 'kaguya-s02e10.ass');
-
-  assert.equal(findActiveSubtitleText(cues, 238.48), '');
-  assert.equal(findActiveSubtitleText(cues, 238.5), 'A question veiled as an insult!');
-  assert.equal(findActiveSubtitleText(cues, 239), 'A question veiled as an insult!');
-  assert.equal(findActiveSubtitleText(cues, 240.34), '');
-});
-
-test('parsed secondary text drops a reconstructed grid of positioned sign fragments', () => {
-  const signFragment = (text: string, x: number, y: number) =>
-    `Dialogue: 1,0:00:01.00,0:00:03.00,Signs,,0,0,0,,{\\pos(${x},${y})\\t(0,100,\\fscx101)}${text}`;
-  const ass = [
-    '[Events]',
-    'Format: Layer, Start, End, Style, Name, MarginL, MarginR, MarginV, Effect, Text',
-    'Dialogue: 10,0:00:01.00,0:00:03.00,Default,Speaker,0,0,0,,Come on, wake up!',
-    signFragment('Timetable', 1700, 150),
-    signFragment('Mon', 1750, 230),
-    signFragment('Tue', 1850, 230),
-    signFragment('1', 1650, 320),
-    signFragment('2', 1650, 390),
-    signFragment('Civics', 1750, 320),
-    signFragment('Math', 1850, 390),
-    signFragment('PE', 1850, 460),
-  ].join('\n');
-
-  assert.equal(
-    findActiveSubtitleText(parseSubtitleCues(ass, 'kaguya-s02e11.ass'), 2),
-    'Come on, wake up!',
-  );
-});
-
-test('parsed secondary lyrics keep explicit ASS vertical order when durations alternate', () => {
-  const lyric = (options: { start: string; end: string; style: string; y: number; text: string }) =>
-    `Dialogue: 0,0:00:${options.start},0:00:${options.end},${options.style},,0,0,0,fx,{\\move(100,${options.y},120,${options.y})\\t(0,200,\\fscx110)}${options.text}\\N{\\p1}m 0 0 l 0 5`;
-  const ass = [
-    '[Events]',
-    'Format: Layer, Start, End, Style, Name, MarginL, MarginR, MarginV, Effect, Text',
-    lyric({
-      start: '01.00',
-      end: '02.20',
-      style: 'ed_romaji',
-      y: 66,
-      text: 'ima wo kakusarechau mae ni',
-    }),
-    lyric({
-      start: '01.00',
-      end: '02.00',
-      style: 'ed_english',
-      y: 1020,
-      text: 'Before the present moment gets hidden away.',
-    }),
-    lyric({
-      start: '03.00',
-      end: '04.00',
-      style: 'ed_romaji',
-      y: 66,
-      text: 'ame mitai ni hikatteru',
-    }),
-    lyric({
-      start: '03.00',
-      end: '04.20',
-      style: 'ed_english',
-      y: 1020,
-      text: 'Is shining like rain.',
-    }),
-  ].join('\n');
-  const cues = parseSubtitleCues(ass, 'polar-opposites-s01e08.ass');
-
-  assert.equal(
-    findActiveSubtitleText(cues, 1.5),
-    'ima wo kakusarechau mae ni\nBefore the present moment gets hidden away.',
-  );
-  assert.equal(findActiveSubtitleText(cues, 3.5), 'ame mitai ni hikatteru\nIs shining like rain.');
-});
-
-test('unpositioned secondary lyrics fall back to ASS source order', () => {
-  const ass = [
-    '[Events]',
-    'Format: Layer, Start, End, Style, Name, MarginL, MarginR, MarginV, Effect, Text',
-    'Dialogue: 0,0:00:01.00,0:00:02.20,ED Romaji,,0,0,0,,ima wo kakusarechau mae ni',
-    'Dialogue: 0,0:00:01.00,0:00:02.00,ED English,,0,0,0,,Before the present moment gets hidden away.',
-  ].join('\n');
-
-  assert.equal(
-    findActiveSubtitleText(parseSubtitleCues(ass, 'ending.ass'), 1.5),
-    'ima wo kakusarechau mae ni\nBefore the present moment gets hidden away.',
-  );
-});
-
-test('findActiveSubtitleText keeps a canonical ASS cue for its generated animation span', () => {
-  const poof = {
-    startTime: 1110.67,
-    endTime: 1110.71,
-    text: 'POOF',
-    source: 'canonical-ass' as const,
-    animationStartTime: 1110.67,
-    animationEndTime: 1111.59,
-  };
-
-  assert.equal(findActiveSubtitleText([poof], 1111.58), 'POOF');
-  assert.equal(findActiveSubtitleText([poof], 1111.59), '');
-});
-
-test('ASS fragment karaoke stays separated by style with authored word spacing', () => {
-  const lineEvents = (
-    style: string,
-    fragments: readonly string[],
-    y: number,
-    baseTime = 1,
-  ): string[] => {
-    const events: string[] = [];
-    for (const layer of [0, 1]) {
-      fragments.forEach((fragment, index) => {
-        const x = 100 + index * 40;
-        const start = (baseTime + index * 0.25).toFixed(2).padStart(5, '0');
-        const end = (baseTime + 3 + index * 0.2).toFixed(2).padStart(5, '0');
-        events.push(
-          `Dialogue: ${layer},0:00:${start},0:00:${end},${style},,0,0,0,,{\\pos(${x},${y})\\t(0,200,\\fscx110)}${fragment}\\N{\\p1}m 0 0 l 0 10`,
-        );
-      });
-    }
-    return events;
-  };
-  const ass = [
-    '[Events]',
-    'Format: Layer, Start, End, Style, Name, MarginL, MarginR, MarginV, Effect, Text',
-    ...lineEvents('ed_romaji', ['ji', 'gu', 'za', 'gu ', 'na', 'mi'], 70),
-    ...lineEvents('ed_english', ['Pas', 'si', 'ng ', 'thro', 'u', 'gh '], 110),
-    ...lineEvents('op_english', ['I', 'want', 'to', 'go'], 110, 7),
-  ].join('\n');
-
-  assert.equal(
-    findActiveSubtitleText(parseSubtitleCues(ass, 'ending.ass'), 2.5),
-    'jiguzagu nami\nPassing through',
-  );
-  // Some generated scripts discard spaces and retain only positioned chunks. Joining
-  // without invented separators avoids turning one word into spaced syllables.
-  assert.equal(findActiveSubtitleText(parseSubtitleCues(ass, 'ending.ass'), 8.5), 'Iwanttogo');
-});
-
-test('findActiveSubtitleText keeps a complete reconstructed line over entrance fragments', () => {
-  const current = {
-    startTime: 1,
-    endTime: 4,
-    text: 'Complete current line',
-    source: 'reconstructed-ass' as const,
-    assStyle: 'op_english',
-  };
-  const nextEntrance = {
-    startTime: 3.8,
-    endTime: 4.2,
-    text: 'Ne',
-    source: 'reconstructed-ass' as const,
-    assStyle: 'op_english',
-  };
-  const nextLine = {
-    startTime: 4,
-    endTime: 7,
-    text: 'Next complete line',
-    source: 'reconstructed-ass' as const,
-    assStyle: 'op_english',
-  };
-
-  assert.equal(findActiveSubtitleText([current, nextEntrance], 3.9), current.text);
-  assert.equal(findActiveSubtitleText([current, nextEntrance, nextLine], 4.1), nextLine.text);
-});
-
 test('secondary track controller parses the selected ASS file before publishing', async () => {
  const broadcasts: string[] = [];
  let currentText = '';
@@ -1,5 +1,4 @@
 import type { SubtitleCue } from '../../types/subtitle';
-import { flattenedSecondarySubtitleLineIdentity } from '../../core/services/secondary-subtitle-line-identity';

 type SecondarySubtitleMpvClient = {
  connected?: boolean;
@@ -59,108 +58,16 @@ function buildSelectedTrackIdentity(
  ]);
 }

-type IndexedSubtitleCue = { cue: SubtitleCue; index: number };
-
-function compareAuthoredSubtitleOrder(left: IndexedSubtitleCue, right: IndexedSubtitleCue): number {
-  const leftLayout = left.cue.assLayout;
-  const rightLayout = right.cue.assLayout;
-  if (leftLayout?.kind === 'positioned' && rightLayout?.kind === 'positioned') {
-    const verticalOrder = leftLayout.y - rightLayout.y;
-    if (verticalOrder !== 0) return verticalOrder;
-  }
-  if (leftLayout && rightLayout) {
-    const sourceOrder = leftLayout.sourceOrder - rightLayout.sourceOrder;
-    if (sourceOrder !== 0) return sourceOrder;
-  }
-  return left.index - right.index;
-}
-
 export function findActiveSubtitleText(cues: readonly SubtitleCue[], timeSeconds: number): string {
  if (!Number.isFinite(timeSeconds)) return '';

-  const authoredCanonical = cues.filter(
-    (cue) =>
-      cue.source === 'canonical-ass' && cue.startTime <= timeSeconds && cue.endTime > timeSeconds,
-  );
-  const selectedCanonical = new Set<SubtitleCue>(authoredCanonical);
-  if (selectedCanonical.size === 0) {
-    const animatedCanonical = cues.filter(
-      (cue) =>
-        cue.source === 'canonical-ass' &&
-        (cue.animationStartTime ?? cue.startTime) <= timeSeconds &&
-        (cue.animationEndTime ?? cue.endTime) > timeSeconds,
-    );
-    const nearestDistance = animatedCanonical.reduce((nearest, cue) => {
-      const distance =
-        timeSeconds < cue.startTime
-          ? cue.startTime - timeSeconds
-          : Math.max(0, timeSeconds - cue.endTime);
-      return Math.min(nearest, distance);
-    }, Infinity);
-    for (const cue of animatedCanonical) {
-      const distance =
-        timeSeconds < cue.startTime
-          ? cue.startTime - timeSeconds
-          : Math.max(0, timeSeconds - cue.endTime);
-      if (distance === nearestDistance) {
-        selectedCanonical.add(cue);
-      }
-    }
-  }
-
-  const activeReconstructed = cues.filter(
-    (cue) =>
-      cue.source === 'reconstructed-ass' &&
-      cue.assLayout?.kind !== 'fragment-grid' &&
-      cue.startTime <= timeSeconds &&
-      cue.endTime > timeSeconds,
-  );
-  const reconstructedByStyle = new Map<string, SubtitleCue>();
-  for (const cue of activeReconstructed) {
-    const style = cue.assStyle ?? '';
-    const existing = reconstructedByStyle.get(style);
-    if (!existing) {
-      reconstructedByStyle.set(style, cue);
-      continue;
-    }
-    const duration = cue.endTime - cue.startTime;
-    const existingDuration = existing.endTime - existing.startTime;
-    if (
-      duration > existingDuration ||
-      (duration === existingDuration && cue.text.length > existing.text.length) ||
-      (duration === existingDuration &&
-        cue.text.length === existing.text.length &&
-        cue.startTime > existing.startTime)
-    ) {
-      reconstructedByStyle.set(style, cue);
-    }
-  }
-  const selectedReconstructed = new Set(reconstructedByStyle.values());
-
-  const seenExact = new Set<string>();
-  const seenFlattened = new Set<string>();
+  const seen = new Set<string>();
  const activeText: string[] = [];
-  const activeCues: IndexedSubtitleCue[] = [];
-  cues.forEach((cue, index) => {
-    const active =
-      cue.source === 'canonical-ass'
-        ? selectedCanonical.has(cue)
-        : cue.source === 'reconstructed-ass'
-          ? selectedReconstructed.has(cue)
-          : cue.startTime <= timeSeconds && cue.endTime > timeSeconds;
-    if (active) activeCues.push({ cue, index });
-  });
-  activeCues.sort(compareAuthoredSubtitleOrder);
-
-  for (const { cue } of activeCues) {
+  for (const cue of cues) {
+    if (cue.startTime > timeSeconds || cue.endTime <= timeSeconds) continue;
    const text = cue.text.trim();
-    const compactText = text.replace(/\s+/gu, '');
-    if (!compactText || seenExact.has(compactText)) continue;
-    seenExact.add(compactText);
-
-    const flattenedIdentity = flattenedSecondarySubtitleLineIdentity(text);
-    if (flattenedIdentity && seenFlattened.has(flattenedIdentity)) continue;
-    if (flattenedIdentity) seenFlattened.add(flattenedIdentity);
+    if (!text || seen.has(text)) continue;
+    seen.add(text);
    activeText.push(text);
  }
  return activeText.join('\n');
@@ -13,7 +13,7 @@ import {
 } from './support-assets';

 type SupportAssetsResultWithComponent = SupportAssetsUpdateResult & {
-  component?: 'theme' | 'thumbnailer' | 'plugin';
+  component?: 'theme' | 'plugin';
 };

 function sha256(data: Buffer): string {
@@ -22,30 +22,18 @@ function sha256(data: Buffer): string {

 function makeSupportAssetsArchive(options?: {
  themeContent?: string;
-  thumbnailerContent?: string;
-  includeThumbnailer?: boolean;
  pluginVersion?: string | null;
  pluginMainContent?: string;
  extraPluginFiles?: Array<{ relativePath: string; content: string }>;
 }): { archive: Buffer; tempDir: string } {
  const themeContent = options?.themeContent ?? 'new theme\n';
-  const thumbnailerContent = options?.thumbnailerContent ?? '[Thumbnailer Entry]\n';
  const pluginVersion = options && 'pluginVersion' in options ? options.pluginVersion : '0.12.0';
  const pluginMainContent = options?.pluginMainContent ?? 'new plugin\n';
  const extraPluginFiles = options?.extraPluginFiles ?? [];
  const tempDir = fs.mkdtempSync(path.join(os.tmpdir(), 'subminer-support-assets-test-'));
  fs.mkdirSync(path.join(tempDir, 'assets/themes'), { recursive: true });
-  if (options?.includeThumbnailer !== false) {
-    fs.mkdirSync(path.join(tempDir, 'assets/thumbnailers'), { recursive: true });
-  }
  fs.mkdirSync(path.join(tempDir, 'plugin/subminer'), { recursive: true });
  fs.writeFileSync(path.join(tempDir, 'assets/themes/subminer.rasi'), themeContent);
-  if (options?.includeThumbnailer !== false) {
-    fs.writeFileSync(
-      path.join(tempDir, 'assets/thumbnailers/subminer-ffmpegthumbnailer.thumbnailer'),
-      thumbnailerContent,
-    );
-  }
  fs.writeFileSync(path.join(tempDir, 'plugin/subminer/main.lua'), pluginMainContent);
  if (pluginVersion !== null) {
    fs.writeFileSync(
@@ -105,7 +93,7 @@ test('detectSupportAssetDataDirs only returns Linux support-asset locations', ()
  );
 });

-test('buildProtectedSupportAssetsCommand installs theme, thumbnailer, and plugin assets', () => {
+test('buildProtectedSupportAssetsCommand installs both theme and plugin assets', () => {
  const command = buildProtectedSupportAssetsCommand(
    "https://example.test/subminer assets.tar.gz?sig='abc'",
    'ABCDEF1234',
@@ -122,28 +110,11 @@ test('buildProtectedSupportAssetsCommand installs theme, thumbnailer, and plugin
    command,
    /printf '%s  %s\\n' 'abcdef1234' "\$tmp\/subminer-assets\.tar\.gz" \| sha256sum -c -/,
  );
-  const requiredAssetChecks = [
-    'test -f "$tmp/assets/themes/subminer.rasi"',
-    'test -f "$tmp/assets/thumbnailers/subminer-ffmpegthumbnailer.thumbnailer"',
-    'test -f "$tmp/plugin/subminer/main.lua"',
-    'test -f "$tmp/plugin/subminer/version.lua"',
-  ];
-  const firstSudoIndex = command.indexOf('sudo ');
-  assert.notEqual(firstSudoIndex, -1);
-  for (const check of requiredAssetChecks) {
-    const checkIndex = command.indexOf(check);
-    assert.notEqual(checkIndex, -1);
-    assert.ok(checkIndex < firstSudoIndex);
-  }
  assert.match(command, /sudo mkdir -p '\/usr\/local\/share\/SubMiner'\\''s data'\/themes/);
  assert.match(
    command,
    /sudo cp "\$tmp\/assets\/themes\/subminer\.rasi" '\/usr\/local\/share\/SubMiner'\\''s data'\/themes\/subminer\.rasi/,
  );
-  assert.match(
-    command,
-    /sudo cp "\$tmp\/assets\/thumbnailers\/subminer-ffmpegthumbnailer\.thumbnailer" .*thumbnailers\/subminer-ffmpegthumbnailer\.thumbnailer/,
-  );
  assert.match(command, /sudo mkdir -p '\/usr\/local\/share\/SubMiner'\\''s data'\/plugin/);
  assert.match(command, /sudo rm -rf .*plugin\/subminer\.next/);
  assert.match(command, /sudo cp -R "\$tmp\/plugin\/subminer" .*plugin\/subminer\.next/);
@@ -238,12 +209,6 @@ test('updateSupportAssetsFromRelease installs missing plugin into a root with a
        path: dataDir,
        message: 'Updated theme.',
      },
-      {
-        status: 'updated',
-        component: 'thumbnailer',
-        path: dataDir,
-        message: 'Installed rofi thumbnailer.',
-      },
      {
        status: 'updated',
        component: 'plugin',
@@ -255,13 +220,6 @@ test('updateSupportAssetsFromRelease installs missing plugin into a root with a
      fs.readFileSync(path.join(dataDir, 'themes/subminer.rasi'), 'utf8'),
      'new theme\n',
    );
-    assert.equal(
-      fs.readFileSync(
-        path.join(dataDir, 'thumbnailers/subminer-ffmpegthumbnailer.thumbnailer'),
-        'utf8',
-      ),
-      '[Thumbnailer Entry]\n',
-    );
    assert.equal(
      fs.readFileSync(path.join(dataDir, 'plugin/subminer/main.lua'), 'utf8'),
      'new plugin\n',
@@ -387,13 +345,8 @@ test('updateSupportAssetsFromRelease skips identical theme and up-to-date plugin
  const xdgDataHome = fs.mkdtempSync(path.join(os.tmpdir(), 'subminer-xdg-data-'));
  const dataDir = path.posix.join(xdgDataHome, 'SubMiner');
  fs.mkdirSync(path.join(dataDir, 'themes'), { recursive: true });
-  fs.mkdirSync(path.join(dataDir, 'thumbnailers'), { recursive: true });
  fs.mkdirSync(path.join(dataDir, 'plugin/subminer'), { recursive: true });
  fs.writeFileSync(path.join(dataDir, 'themes/subminer.rasi'), 'same theme\n');
-  fs.writeFileSync(
-    path.join(dataDir, 'thumbnailers/subminer-ffmpegthumbnailer.thumbnailer'),
-    '[Thumbnailer Entry]\n',
-  );
  fs.writeFileSync(path.join(dataDir, 'plugin/subminer/main.lua'), 'same plugin\n');
  fs.writeFileSync(
    path.join(dataDir, 'plugin/subminer/version.lua'),
@@ -418,12 +371,6 @@ test('updateSupportAssetsFromRelease skips identical theme and up-to-date plugin
        path: dataDir,
        message: 'Theme already up to date.',
      },
-      {
-        status: 'skipped',
-        component: 'thumbnailer',
-        path: dataDir,
-        message: 'Rofi thumbnailer already up to date.',
-      },
      {
        status: 'skipped',
        component: 'plugin',
@@ -449,13 +396,8 @@ test('updateSupportAssetsFromRelease updates changed theme and outdated plugin w
  const xdgDataHome = fs.mkdtempSync(path.join(os.tmpdir(), 'subminer-xdg-data-'));
  const dataDir = path.posix.join(xdgDataHome, 'SubMiner');
  fs.mkdirSync(path.join(dataDir, 'themes'), { recursive: true });
-  fs.mkdirSync(path.join(dataDir, 'thumbnailers'), { recursive: true });
  fs.mkdirSync(path.join(dataDir, 'plugin/subminer'), { recursive: true });
  fs.writeFileSync(path.join(dataDir, 'themes/subminer.rasi'), 'old theme\n');
-  fs.writeFileSync(
-    path.join(dataDir, 'thumbnailers/subminer-ffmpegthumbnailer.thumbnailer'),
-    '[Old Thumbnailer]\n',
-  );
  fs.writeFileSync(path.join(dataDir, 'plugin/subminer/main.lua'), 'old plugin\n');
  fs.writeFileSync(
    path.join(dataDir, 'plugin/subminer/version.lua'),
@@ -464,7 +406,6 @@ test('updateSupportAssetsFromRelease updates changed theme and outdated plugin w
  fs.writeFileSync(path.join(dataDir, 'plugin/subminer/stale.lua'), 'stale\n');
  const { archive, tempDir } = makeSupportAssetsArchive({
    themeContent: 'new theme\n',
-    thumbnailerContent: '[Thumbnailer Entry]\n',
    pluginVersion: '0.12.0',
    pluginMainContent: 'new plugin main\n',
    extraPluginFiles: [{ relativePath: 'fresh.lua', content: 'fresh\n' }],
@@ -483,12 +424,6 @@ test('updateSupportAssetsFromRelease updates changed theme and outdated plugin w
        path: dataDir,
        message: 'Updated theme.',
      },
-      {
-        status: 'updated',
-        component: 'thumbnailer',
-        path: dataDir,
-        message: 'Updated rofi thumbnailer.',
-      },
      {
        status: 'updated',
        component: 'plugin',
@@ -500,13 +435,6 @@ test('updateSupportAssetsFromRelease updates changed theme and outdated plugin w
      fs.readFileSync(path.join(dataDir, 'themes/subminer.rasi'), 'utf8'),
      'new theme\n',
    );
-    assert.equal(
-      fs.readFileSync(
-        path.join(dataDir, 'thumbnailers/subminer-ffmpegthumbnailer.thumbnailer'),
-        'utf8',
-      ),
-      '[Thumbnailer Entry]\n',
-    );
    assert.equal(
      fs.readFileSync(path.join(dataDir, 'plugin/subminer/main.lua'), 'utf8'),
      'new plugin main\n',
@@ -551,12 +479,6 @@ test('updateSupportAssetsFromRelease returns protected commands for managed root
          path: dataDir,
          command: true,
        },
-        {
-          status: 'protected',
-          component: 'thumbnailer',
-          path: dataDir,
-          command: true,
-        },
        {
          status: 'protected',
          component: 'plugin',
@@ -566,10 +488,6 @@ test('updateSupportAssetsFromRelease returns protected commands for managed root
      ],
    );
    assert.match(results[0]?.command ?? '', /themes\/subminer\.rasi/);
-    assert.match(
-      results[0]?.command ?? '',
-      /thumbnailers\/subminer-ffmpegthumbnailer\.thumbnailer/,
-    );
    assert.match(results[0]?.command ?? '', /plugin\/subminer/);
  } finally {
    fs.chmodSync(dataDir, originalMode);
@@ -604,25 +522,3 @@ test('updateSupportAssetsFromRelease returns missing-asset when release plugin v
    fs.rmSync(tempDir, { recursive: true, force: true });
  }
 });
-
-test('updateSupportAssetsFromRelease rejects archives without the rofi thumbnailer', async () => {
-  const xdgDataHome = fs.mkdtempSync(path.join(os.tmpdir(), 'subminer-xdg-data-'));
-  const dataDir = path.posix.join(xdgDataHome, 'SubMiner');
-  fs.mkdirSync(path.join(dataDir, 'themes'), { recursive: true });
-  fs.writeFileSync(path.join(dataDir, 'themes/subminer.rasi'), 'managed theme\n');
-  const { archive, tempDir } = makeSupportAssetsArchive({ includeThumbnailer: false });
-
-  try {
-    const results = await runLinuxSupportAssetUpdate({ archive, xdgDataHome });
-
-    assert.deepEqual(results, [
-      {
-        status: 'missing-asset',
-        message: 'Support asset archive is missing the rofi thumbnailer.',
-      },
-    ]);
-  } finally {
-    fs.rmSync(xdgDataHome, { recursive: true, force: true });
-    fs.rmSync(tempDir, { recursive: true, force: true });
-  }
-});
@@ -9,17 +9,13 @@ import { compareSemverLike, findReleaseAsset } from './release-assets';

 const execFileAsync = promisify(execFile);
 const THEME_RELATIVE_PATH = path.join('themes', 'subminer.rasi');
-const THUMBNAILER_RELATIVE_PATH = path.join(
-  'thumbnailers',
-  'subminer-ffmpegthumbnailer.thumbnailer',
-);
 const PLUGIN_ENTRYPOINT_RELATIVE_PATH = path.join('plugin', 'subminer', 'main.lua');
 const PLUGIN_VERSION_RELATIVE_PATH = path.join('plugin', 'subminer', 'version.lua');
 const PLUGIN_DIR_RELATIVE_PATH = path.join('plugin', 'subminer');

 export interface SupportAssetsUpdateResult {
  status: 'updated' | 'skipped' | 'protected' | 'hash-mismatch' | 'missing-asset';
-  component?: 'theme' | 'thumbnailer' | 'plugin';
+  component?: 'theme' | 'plugin';
  path?: string;
  command?: string;
  message?: string;
@@ -73,12 +69,11 @@ async function readInstalledPluginVersion(pluginDir: string): Promise<string | n
 async function detectManagedSupportAssetDataDirs(dataDirs: string[]): Promise<string[]> {
  const managedDataDirs: string[] = [];
  for (const dataDir of dataDirs) {
-    const [hasTheme, hasThumbnailer, hasPlugin] = await Promise.all([
+    const [hasTheme, hasPlugin] = await Promise.all([
      pathExists(path.join(dataDir, THEME_RELATIVE_PATH)),
-      pathExists(path.join(dataDir, THUMBNAILER_RELATIVE_PATH)),
      pathExists(path.join(dataDir, PLUGIN_ENTRYPOINT_RELATIVE_PATH)),
    ]);
-    if (hasTheme || hasThumbnailer || hasPlugin) {
+    if (hasTheme || hasPlugin) {
      managedDataDirs.push(dataDir);
    }
  }
@@ -168,14 +163,8 @@ export function buildProtectedSupportAssetsCommand(
    `curl -fSL ${shellQuote(assetUrl)} -o "$tmp/subminer-assets.tar.gz"`,
    `printf '%s  %s\\n' ${quotedExpectedSha256} "$tmp/subminer-assets.tar.gz" | sha256sum -c -`,
    'tar -xzf "$tmp/subminer-assets.tar.gz" -C "$tmp"',
-    'test -f "$tmp/assets/themes/subminer.rasi"',
-    'test -f "$tmp/assets/thumbnailers/subminer-ffmpegthumbnailer.thumbnailer"',
-    'test -f "$tmp/plugin/subminer/main.lua"',
-    'test -f "$tmp/plugin/subminer/version.lua"',
    `sudo mkdir -p ${quotedDir}/themes`,
    `sudo cp "$tmp/assets/themes/subminer.rasi" ${quotedDir}/themes/subminer.rasi`,
-    `sudo mkdir -p ${quotedDir}/thumbnailers`,
-    `sudo cp "$tmp/assets/thumbnailers/subminer-ffmpegthumbnailer.thumbnailer" ${quotedDir}/thumbnailers/subminer-ffmpegthumbnailer.thumbnailer`,
    `sudo mkdir -p ${quotedDir}/plugin`,
    `sudo rm -rf ${quotedStagedPluginDir} ${quotedBackupPluginDir}`,
    `sudo cp -R "$tmp/plugin/subminer" ${quotedStagedPluginDir}`,
@@ -227,12 +216,6 @@ export async function updateSupportAssetsFromRelease(options: {
          dataDir,
          'Support asset path is not a directory.',
        ),
-        makeSupportAssetResult(
-          'skipped',
-          'thumbnailer',
-          dataDir,
-          'Support asset path is not a directory.',
-        ),
        makeSupportAssetResult(
          'skipped',
          'plugin',
@@ -261,13 +244,6 @@ export async function updateSupportAssetsFromRelease(options: {
        'Theme install requires a manual command.',
        command,
      ),
-      makeSupportAssetResult(
-        'protected',
-        'thumbnailer',
-        dataDir,
-        'Rofi thumbnailer install requires a manual command.',
-        command,
-      ),
      makeSupportAssetResult(
        'protected',
        'plugin',
@@ -308,17 +284,6 @@ export async function updateSupportAssetsFromRelease(options: {
    }
    const themeBytes = await fs.promises.readFile(themeSourcePath);

-    const thumbnailerSourcePath = path.join(tempDir, 'assets', THUMBNAILER_RELATIVE_PATH);
-    if (!(await pathExists(thumbnailerSourcePath))) {
-      return [
-        {
-          status: 'missing-asset',
-          message: 'Support asset archive is missing the rofi thumbnailer.',
-        },
-      ];
-    }
-    const thumbnailerBytes = await fs.promises.readFile(thumbnailerSourcePath);
-
    const sourcePluginDir = path.join(tempDir, PLUGIN_DIR_RELATIVE_PATH);
    const sourcePluginEntrypoint = path.join(tempDir, PLUGIN_ENTRYPOINT_RELATIVE_PATH);
    if (!(await pathExists(sourcePluginEntrypoint))) {
@@ -363,33 +328,6 @@ export async function updateSupportAssetsFromRelease(options: {
        );
      }

-      const targetThumbnailerPath = path.join(dataDir, THUMBNAILER_RELATIVE_PATH);
-      const existingThumbnailerBytes = await readFileIfExists(targetThumbnailerPath);
-      if (
-        existingThumbnailerBytes &&
-        Buffer.compare(existingThumbnailerBytes, thumbnailerBytes) === 0
-      ) {
-        results.push(
-          makeSupportAssetResult(
-            'skipped',
-            'thumbnailer',
-            dataDir,
-            'Rofi thumbnailer already up to date.',
-          ),
-        );
-      } else {
-        await fs.promises.mkdir(path.dirname(targetThumbnailerPath), { recursive: true });
-        await fs.promises.writeFile(targetThumbnailerPath, thumbnailerBytes);
-        results.push(
-          makeSupportAssetResult(
-            'updated',
-            'thumbnailer',
-            dataDir,
-            existingThumbnailerBytes ? 'Updated rofi thumbnailer.' : 'Installed rofi thumbnailer.',
-          ),
-        );
-      }
-
      const targetPluginDir = path.join(dataDir, PLUGIN_DIR_RELATIVE_PATH);
      const targetPluginEntrypoint = path.join(dataDir, PLUGIN_ENTRYPOINT_RELATIVE_PATH);
      const installedPluginVersion = await readInstalledPluginVersion(targetPluginDir);
@@ -0,0 +1,133 @@
+import assert from 'node:assert/strict';
+import fs from 'node:fs';
+import os from 'node:os';
+import path from 'node:path';
+import test from 'node:test';
+import {
+  assertYomitanDictionaryMutationSafe,
+  observeYomitanDictionaryCount,
+} from './yomitan-dictionary-integrity';
+
+function withTempDir(run: (directory: string) => void): void {
+  const directory = fs.mkdtempSync(path.join(os.tmpdir(), 'subminer-dictionary-integrity-'));
+  try {
+    run(directory);
+  } finally {
+    fs.rmSync(directory, { recursive: true, force: true });
+  }
+}
+
+test('dictionary integrity observation establishes and updates a non-empty baseline', () => {
+  withTempDir((userDataPath) => {
+    assert.deepEqual(observeYomitanDictionaryCount(userDataPath, 5), {
+      safe: true,
+      previousCount: null,
+    });
+    assert.deepEqual(observeYomitanDictionaryCount(userDataPath, 3), {
+      safe: true,
+      previousCount: 5,
+    });
+    const statePath = path.join(userDataPath, 'yomitan-dictionary-integrity.json');
+    const unchangedTimestamp = new Date('2000-01-01T00:00:00.000Z');
+    fs.utimesSync(statePath, unchangedTimestamp, unchangedTimestamp);
+    assert.deepEqual(observeYomitanDictionaryCount(userDataPath, 3), {
+      safe: true,
+      previousCount: 3,
+    });
+    assert.equal(fs.statSync(statePath).mtimeMs, unchangedTimestamp.getTime());
+    assert.deepEqual(JSON.parse(fs.readFileSync(statePath, 'utf8')), { lastKnownNonEmptyCount: 3 });
+    assert.deepEqual(fs.readdirSync(userDataPath), ['yomitan-dictionary-integrity.json']);
+  });
+});
+
+test('dictionary integrity permits an empty profile before dictionaries are installed', () => {
+  withTempDir((userDataPath) => {
+    assert.deepEqual(observeYomitanDictionaryCount(userDataPath, 0), {
+      safe: true,
+      previousCount: null,
+    });
+  });
+});
+
+test('dictionary integrity rejects invalid counts without creating a safety record', () => {
+  withTempDir((userDataPath) => {
+    for (const invalidCount of [Number.NaN, Number.POSITIVE_INFINITY, -1]) {
+      assert.deepEqual(observeYomitanDictionaryCount(userDataPath, invalidCount), {
+        safe: false,
+        previousCount: null,
+        message: 'SubMiner could not verify Yomitan dictionary storage: invalid dictionary count.',
+      });
+    }
+
+    assert.equal(
+      fs.existsSync(path.join(userDataPath, 'yomitan-dictionary-integrity.json')),
+      false,
+    );
+  });
+});
+
+test('dictionary integrity migrates the previous count from first-run setup state', () => {
+  withTempDir((userDataPath) => {
+    fs.writeFileSync(
+      path.join(userDataPath, 'setup-state.json'),
+      JSON.stringify({
+        version: 4,
+        status: 'completed',
+        completedAt: '2026-08-18T00:00:00.000Z',
+        completionSource: 'user',
+        yomitanSetupMode: 'internal',
+        lastSeenYomitanDictionaryCount: 4,
+        pluginInstallStatus: 'installed',
+        pluginInstallPathSummary: null,
+        windowsMpvShortcutPreferences: {
+          startMenuEnabled: true,
+          desktopEnabled: false,
+        },
+        windowsMpvShortcutLastStatus: 'installed',
+        bunInstallStatus: 'installed',
+        launcherInstallStatus: 'installed',
+        launcherInstallPath: '/home/tester/.local/bin/subminer',
+      }),
+      'utf8',
+    );
+
+    assert.throws(
+      () => assertYomitanDictionaryMutationSafe(userDataPath, 0),
+      /reported zero dictionaries after previously reporting 4/,
+    );
+  });
+});
+
+test('dictionary integrity blocks automatic mutation after a non-empty profile becomes empty', () => {
+  withTempDir((userDataPath) => {
+    observeYomitanDictionaryCount(userDataPath, 6);
+
+    assert.throws(
+      () => assertYomitanDictionaryMutationSafe(userDataPath, 0),
+      /reported zero dictionaries after previously reporting 6/,
+    );
+    assert.deepEqual(observeYomitanDictionaryCount(userDataPath, 0), {
+      safe: false,
+      previousCount: 6,
+      message:
+        'Yomitan reported zero dictionaries after previously reporting 6. SubMiner blocked automatic dictionary changes because Chromium storage may have been reset. Close SubMiner and restore or inspect the profile before changing dictionaries.',
+    });
+  });
+});
+
+test('dictionary integrity fails closed when its state is malformed', () => {
+  withTempDir((userDataPath) => {
+    const statePath = path.join(userDataPath, 'yomitan-dictionary-integrity.json');
+    fs.writeFileSync(statePath, '{}', 'utf8');
+
+    assert.throws(
+      () => assertYomitanDictionaryMutationSafe(userDataPath, 2),
+      (error: unknown) => {
+        assert.ok(error instanceof Error);
+        assert.match(error.message, /could not verify Yomitan dictionary storage/);
+        assert.equal(error.message.includes(statePath), true);
+        return true;
+      },
+    );
+  });
+});
@@ -0,0 +1,112 @@
+import fs from 'node:fs';
+import path from 'node:path';
+import { writeTextFileAtomicallyDurable } from '../../shared/fs-utils';
+import { getSetupStatePath, readSetupState } from '../../shared/setup-state';
+
+const INTEGRITY_STATE_FILE_NAME = 'yomitan-dictionary-integrity.json';
+
+type DictionaryIntegrityState = {
+  lastKnownNonEmptyCount: number;
+};
+
+export type DictionaryIntegrityObservation =
+  | { safe: true; previousCount: number | null }
+  | { safe: false; previousCount: number | null; message: string };
+
+function getStatePath(userDataPath: string): string {
+  return path.join(userDataPath, INTEGRITY_STATE_FILE_NAME);
+}
+
+function readState(statePath: string): DictionaryIntegrityState | null {
+  if (!fs.existsSync(statePath)) return null;
+  const parsed = JSON.parse(
+    fs.readFileSync(statePath, 'utf8'),
+  ) as Partial<DictionaryIntegrityState>;
+  const lastKnownNonEmptyCount = parsed.lastKnownNonEmptyCount;
+  if (
+    typeof lastKnownNonEmptyCount !== 'number' ||
+    !Number.isSafeInteger(lastKnownNonEmptyCount) ||
+    lastKnownNonEmptyCount <= 0
+  ) {
+    throw new Error('The dictionary integrity record has an invalid format.');
+  }
+  return { lastKnownNonEmptyCount };
+}
+
+function writeState(statePath: string, state: DictionaryIntegrityState): void {
+  writeTextFileAtomicallyDurable(statePath, `${JSON.stringify(state, null, 2)}\n`);
+}
+
+function readLegacySetupCount(userDataPath: string): number | null {
+  const setupState = readSetupState(getSetupStatePath(userDataPath));
+  return setupState && setupState.lastSeenYomitanDictionaryCount > 0
+    ? setupState.lastSeenYomitanDictionaryCount
+    : null;
+}
+
+export function observeYomitanDictionaryCount(
+  userDataPath: string,
+  dictionaryCount: number,
+): DictionaryIntegrityObservation {
+  if (!Number.isSafeInteger(dictionaryCount) || dictionaryCount < 0) {
+    return {
+      safe: false,
+      previousCount: null,
+      message: 'SubMiner could not verify Yomitan dictionary storage: invalid dictionary count.',
+    };
+  }
+
+  const normalizedCount = dictionaryCount;
+  const statePath = getStatePath(userDataPath);
+  let state: DictionaryIntegrityState | null;
+
+  try {
+    state = readState(statePath);
+    if (state === null) {
+      const legacyCount = readLegacySetupCount(userDataPath);
+      state = legacyCount === null ? null : { lastKnownNonEmptyCount: legacyCount };
+    }
+  } catch (error) {
+    return {
+      safe: false,
+      previousCount: null,
+      message: `SubMiner could not verify Yomitan dictionary storage at ${statePath}: ${(error as Error).message}`,
+    };
+  }
+
+  if (normalizedCount === 0 && state !== null) {
+    return {
+      safe: false,
+      previousCount: state.lastKnownNonEmptyCount,
+      message: [
+        `Yomitan reported zero dictionaries after previously reporting ${state.lastKnownNonEmptyCount}.`,
+        'SubMiner blocked automatic dictionary changes because Chromium storage may have been reset.',
+        'Close SubMiner and restore or inspect the profile before changing dictionaries.',
+      ].join(' '),
+    };
+  }
+
+  if (normalizedCount > 0 && normalizedCount !== state?.lastKnownNonEmptyCount) {
+    try {
+      writeState(statePath, { lastKnownNonEmptyCount: normalizedCount });
+    } catch (error) {
+      return {
+        safe: false,
+        previousCount: state?.lastKnownNonEmptyCount ?? null,
+        message: `SubMiner could not update the Yomitan dictionary integrity record: ${(error as Error).message}`,
+      };
+    }
+  }
+
+  return { safe: true, previousCount: state?.lastKnownNonEmptyCount ?? null };
+}
+
+export function assertYomitanDictionaryMutationSafe(
+  userDataPath: string,
+  dictionaryCount: number,
+): void {
+  const observation = observeYomitanDictionaryCount(userDataPath, dictionaryCount);
+  if (!observation.safe) {
+    throw new Error(observation.message);
+  }
+}
@@ -240,15 +240,14 @@ test('subtitle sidebar modal opens from snapshot and clicking cue seeks playback

  const snapshot: SubtitleSidebarSnapshot = {
    cues: [
-      { startTime: 1, endTime: 3.4, text: 'first' },
+      { startTime: 1, endTime: 2, text: 'first' },
      { startTime: 3, endTime: 4, text: 'second' },
    ],
    currentSubtitle: {
      text: 'second',
-      startTime: 3.5,
+      startTime: 3,
      endTime: 4,
    },
-    currentTimeSec: 3.5,
    config: {
      enabled: true,
      autoOpen: false,
@@ -362,9 +361,6 @@ test('subtitle sidebar modal opens from snapshot and clicking cue seeks playback
    modal.seekToCue(snapshot.cues[0]!);
    assert.deepEqual(mpvCommands.at(-1), ['seek', 1.08, 'absolute+exact']);

-    modal.seekToCue(snapshot.cues[1]!);
-    assert.deepEqual(mpvCommands.at(-1), ['seek', 3.48, 'absolute+exact']);
-
    modal.closeSubtitleSidebarModal();
    assert.deepEqual(visibilityChanges, [true, false]);
    assert.deepEqual(modalNotifications, ['open:subtitle-sidebar', 'close:subtitle-sidebar']);
--- a/Show More
+++ b/Show More
Author	SHA1	Message	Date
sudacode	80ffa26400	fix(storage): address CI and review feedback	2026-08-18 22:42:26 -07:00
sudacode	06b21a68fa	fix(storage): protect Yomitan profiles across Electron runtime changes - Block unsupported or downgraded Electron runtimes before loading profile storage - Isolate development profiles and guard against unexpected dictionary loss	2026-08-18 22:19:47 -07:00