Decouple stats daemon and preserve final mine OSD status

- Run `subminer stats -b` as a dedicated daemon process, independent from the overlay app
- Stop Anki progress spinner before showing final `✓`/`x` mine result so it is not overwritten
- Keep grammar/noise subtitle tokens hoverable while stripping annotation metadata

backlog/tasks/task-195 - Keep-final-card-mine-OSD-result-from-being-overwritten-by-progress-spinner.md

@@ -0,0 +1,64 @@
+---
+id: TASK-195
+title: Keep final card-mine OSD result from being overwritten by progress spinner
+status: Done
+assignee:
+  - Codex
+created_date: '2026-03-18 19:40'
+updated_date: '2026-03-18 19:49'
+labels:
+  - anki
+  - ui
+  - bug
+milestone: m-1
+dependencies: []
+references:
+  - src/anki-integration/ui-feedback.ts
+  - src/anki-integration.ts
+  - src/anki-integration/card-creation.ts
+priority: medium
+ordinal: 105610
+---
+
+## Description
+
+<!-- SECTION:DESCRIPTION:BEGIN -->
+
+When a card mine finishes, the mpv OSD currently tries to show the final status text but the in-flight Anki progress spinner can immediately overwrite it on the next tick. Stop the spinner first, then show a single-line final result with a success/failure marker and the mined-word notification.
+
+<!-- SECTION:DESCRIPTION:END -->
+
+## Acceptance Criteria
+
+<!-- AC:BEGIN -->
+
+- [x] #1 Successful mine/update OSD results render after the spinner is stopped and do not get overwritten by a later spinner tick.
+- [x] #2 Failure results that replace the spinner show an `x` marker and stay visible on the same OSD line.
+- [x] #3 Regression coverage locks the spinner teardown/result-notification ordering.
+<!-- AC:END -->
+
+## Implementation Plan
+
+<!-- SECTION:PLAN:BEGIN -->
+
+1. Add a focused failing regression test around the Anki UI-feedback spinner/result helper.
+2. Add a helper that stops progress before emitting the final OSD result line with `✓`/`x`.
+3. Route mine/update result notifications through that helper, then run targeted verification.
+<!-- SECTION:PLAN:END -->
+
+## Outcome
+
+<!-- SECTION:OUTCOME:BEGIN -->
+
+Added a dedicated Anki UI-feedback result helper that force-clears the in-flight spinner state before emitting the final OSD result line. Successful card-update notifications now render as `✓ Updated card: ...`, and sentence-card creation failures now render as `x Sentence card failed: ...` without a later spinner tick reclaiming the line.
+
+Verification:
+
+- `bun test src/anki-integration/ui-feedback.test.ts`
+- `bun test src/anki-integration/ui-feedback.test.ts src/anki-integration/note-update-workflow.test.ts src/anki-integration.test.ts src/core/services/mining.test.ts src/main/runtime/mining-actions.test.ts`
+- `bun x prettier --check src/anki-integration/ui-feedback.ts src/anki-integration/ui-feedback.test.ts src/anki-integration.ts src/anki-integration/card-creation.ts "backlog/tasks/task-195 - Keep-final-card-mine-OSD-result-from-being-overwritten-by-progress-spinner.md" changes/2026-03-18-mine-osd-spinner-result.md`
+- `bun run changelog:lint`
+- `bash .agents/skills/subminer-change-verification/scripts/verify_subminer_change.sh --lane core src/anki-integration/ui-feedback.ts src/anki-integration/ui-feedback.test.ts src/anki-integration.ts src/anki-integration/card-creation.ts changes/2026-03-18-mine-osd-spinner-result.md`
+- Verifier artifacts: `.tmp/skill-verification/subminer-verify-20260318-194614-uZMrAx/`
+
+<!-- SECTION:OUTCOME:END -->

changes/2026-03-18-mine-osd-spinner-result.md

@@ -0,0 +1,4 @@
+type: fixed
+area: anki
+
+- Fixed card-mine OSD feedback so the final mine result stops the Anki spinner first, then shows a single-line `✓`/`x` status without being overwritten by a later spinner tick.

changes/2026-03-18-stats-daemon-decoupling.md

@@ -0,0 +1,5 @@
+type: fixed
+area: stats
+
+- `subminer stats -b` now runs as a standalone background stats daemon instead of reusing the main SubMiner app process, so the overlay app can still be launched separately for normal video watching.
+- Dashboard word mining still works against the background daemon by using a short-lived hidden helper for the Yomitan add-note flow.

changes/2026-03-18-subtitle-noise-filtering.md

@@ -1,4 +1,5 @@
 type: changed
 area: overlay
 
-- Excluded interjections and sound-effect tokens from subtitle annotation styling so they no longer inherit misleading lexical highlight treatment while still remaining visible and non-interactive in the subtitle line.
+- Excluded interjections and sound-effect tokens from subtitle annotation styling so they no longer inherit misleading lexical highlight treatment while still remaining visible and hoverable as plain subtitle tokens.
+- Expanded subtitle annotation noise filtering to also strip annotation metadata from standalone grammar-only helper tokens such as particles, auxiliaries, adnominals, common explanatory endings like `んです` / `のだ`, and merged trailing quote-particle forms like `...って` while keeping them tokenized for hover lookup.

docs-site/immersion-tracking.md

@@ -26,7 +26,7 @@ The same immersion data powers the stats dashboard.
 
 - In-app overlay: focus the visible overlay, then press the key from `stats.toggleKey` (default: `` ` `` / `Backquote`).
 - Launcher command: run `subminer stats` to start the local stats server on demand and open the dashboard in your browser.
-- Background server: run `subminer stats -b` to start or reuse a dedicated background stats server without keeping the launcher attached, and `subminer stats -s` to stop that background server.
+- Background server: run `subminer stats -b` to start or reuse a dedicated background stats daemon without keeping the launcher attached, and `subminer stats -s` to stop that daemon.
 - Maintenance command: run `subminer stats cleanup` or `subminer stats cleanup -v` to backfill/repair vocabulary metadata (`headword`, `reading`, POS) and purge stale or excluded rows from `imm_words` on demand.
 - Browser page: open `http://127.0.0.1:5175` directly if the local stats server is already running.
 
@@ -80,8 +80,9 @@ Stats server config lives under `stats`:
 - `autoStartServer` starts the local stats HTTP server on launch once immersion tracking is active, or reuses the dedicated background stats server when one is already running.
 - `autoOpenBrowser` controls whether `subminer stats` launches the dashboard URL in your browser after ensuring the server is running.
 - `subminer stats` forces the dashboard server to start even when `autoStartServer` is `false`.
-- `subminer stats -b` starts or reuses the dedicated background stats server and exits after startup acknowledgement.
+- `subminer stats -b` starts or reuses the dedicated background stats daemon and exits after startup acknowledgement.
-- `subminer stats -s` stops the dedicated background stats server without closing any browser tabs.
+- The background stats daemon is separate from the normal SubMiner overlay app, so you can leave it running and still launch SubMiner later to watch or mine from video.
+- `subminer stats -s` stops the dedicated background stats daemon without closing any browser tabs.
 - `subminer stats` fails with an error when `immersionTracking.enabled` is `false`.
 - `subminer stats cleanup` defaults to vocabulary cleanup, repairs stale `headword`, `reading`, and `part_of_speech` values, attempts best-effort MeCab backfill for legacy rows, and removes rows that still fail vocab filtering.
 
@@ -89,7 +90,7 @@ Stats server config lives under `stats`:
 
 The Vocabulary tab's word detail panel shows example lines from your viewing history. Each example line with a valid source file offers three mining buttons:
 
-- **Mine Word** — performs a full Yomitan dictionary lookup for the word (definition, reading, pitch accent, etc.) via the hidden search page, then enriches the card with sentence audio, a screenshot or animated AVIF clip, the highlighted sentence, and metadata extracted from the source video file. Requires Anki and Yomitan dictionaries to be loaded.
+- **Mine Word** — performs a full Yomitan dictionary lookup for the word (definition, reading, pitch accent, etc.) via a short-lived hidden helper, then enriches the card with sentence audio, a screenshot or animated AVIF clip, the highlighted sentence, and metadata extracted from the source video file. Requires Anki and Yomitan dictionaries to be loaded.
 - **Mine Sentence** — creates a sentence card directly with the `IsSentenceCard` flag set (for Lapis/Kiku workflows), along with audio, image, and translation from the secondary subtitle if available.
 - **Mine Audio** — creates an audio-only card with the `IsAudioCard` flag, attaching only the sentence audio clip.
 

docs-site/subtitle-annotations.md

@@ -4,6 +4,8 @@ SubMiner annotates subtitle tokens in real time as they appear in the overlay. F
 
 All four are opt-in and configured under `subtitleStyle`, `ankiConnect.knownWords`, and `ankiConnect.nPlusOne` in your config. They apply independently — you can enable any combination.
 
+Before any of those layers render, SubMiner strips annotation metadata from tokens that are usually just subtitle glue or annotation noise. Standalone particles, auxiliaries, adnominals, common explanatory endings like `んです` / `のだ`, merged trailing quote-particle forms like `...って`, repeated kana interjections, and similar non-lexical helper tokens remain hoverable in the subtitle text, but they render as plain tokens without known-word, N+1, frequency, JLPT, or name-match annotation styling.
+
 ## N+1 Word Highlighting
 
 N+1 highlighting identifies sentences where you know every word except one, making them ideal mining targets. When enabled, SubMiner builds a local cache of your known vocabulary from Anki and highlights tokens accordingly.
@@ -80,6 +82,10 @@ When `sourcePath` is omitted, SubMiner searches default install/runtime location
 Frequency highlighting skips tokens that look like non-lexical noise (kana reduplication, short kana endings like `っ`), even when dictionary ranks exist.
 :::
 
+::: info
+Frequency, JLPT, and N+1 metadata are only shown for tokens that survive the subtitle-annotation noise filter. Standalone grammar tokens like `は`, `です`, and `この` are intentionally left unannotated even if a dictionary can assign them metadata.
+:::
+
 ## JLPT Tagging
 
 JLPT tagging adds colored underlines to tokens based on their JLPT level (N1–N5), giving you an at-a-glance sense of difficulty distribution in each subtitle line.

launcher/commands/command-modules.test.ts

@@ -150,16 +150,17 @@ test('stats command launches attached app command with response path', async ()
   assert.equal(handled, true);
   assert.deepEqual(forwarded, [
     [
-      '--stats',
+      '--stats-daemon-start',
       '--stats-response-path',
       '/tmp/subminer-stats-test/response.json',
+      '--stats-daemon-open-browser',
       '--log-level',
       'debug',
     ],
   ]);
 });
 
-test('stats background command launches detached app command with response path', async () => {
+test('stats background command launches attached daemon control command with response path', async () => {
   const context = createContext();
   context.args.stats = true;
   (context.args as typeof context.args & { statsBackground?: boolean }).statsBackground = true;
@@ -168,11 +169,9 @@ test('stats background command launches detached app command with response path'
   const handled = await runStatsCommand(context, {
     createTempDir: () => '/tmp/subminer-stats-test',
     joinPath: (...parts) => parts.join('/'),
-    runAppCommandAttached: async () => {
+    runAppCommandAttached: async (_appPath, appArgs) => {
-      throw new Error('attached path should not run for stats -b');
-    },
-    launchAppCommandDetached: (_appPath, appArgs) => {
       forwarded.push(appArgs);
+      return 0;
     },
     waitForStatsResponse: async () => ({ ok: true, url: 'http://127.0.0.1:5175' }),
     removeDir: () => {},
@@ -181,10 +180,9 @@ test('stats background command launches detached app command with response path'
   assert.equal(handled, true);
   assert.deepEqual(forwarded, [
     [
-      '--stats',
+      '--stats-daemon-start',
       '--stats-response-path',
       '/tmp/subminer-stats-test/response.json',
-      '--stats-background',
     ],
   ]);
 });
@@ -215,7 +213,12 @@ test('stats command returns after startup response even if app process stays run
   const final = await statsCommand;
   assert.equal(final, true);
   assert.deepEqual(forwarded, [
-    ['--stats', '--stats-response-path', '/tmp/subminer-stats-test/response.json'],
+    [
+      '--stats-daemon-start',
+      '--stats-response-path',
+      '/tmp/subminer-stats-test/response.json',
+      '--stats-daemon-open-browser',
+    ],
   ]);
 });
 
@@ -268,7 +271,11 @@ test('stats stop command forwards stop flag to the app', async () => {
 
   assert.equal(handled, true);
   assert.deepEqual(forwarded, [
-    ['--stats', '--stats-response-path', '/tmp/subminer-stats-test/response.json', '--stats-stop'],
+    [
+      '--stats-daemon-stop',
+      '--stats-response-path',
+      '/tmp/subminer-stats-test/response.json',
+    ],
   ]);
 });
 

launcher/commands/stats-command.ts

@@ -1,7 +1,7 @@
 import fs from 'node:fs';
 import os from 'node:os';
 import path from 'node:path';
-import { launchAppCommandDetached, runAppCommandAttached } from '../mpv.js';
+import { runAppCommandAttached } from '../mpv.js';
 import { sleep } from '../util.js';
 import type { LauncherCommandContext } from './context.js';
 
@@ -20,12 +20,6 @@ type StatsCommandDeps = {
     logLevel: LauncherCommandContext['args']['logLevel'],
     label: string,
   ) => Promise<number>;
-  launchAppCommandDetached: (
-    appPath: string,
-    appArgs: string[],
-    logLevel: LauncherCommandContext['args']['logLevel'],
-    label: string,
-  ) => void;
   waitForStatsResponse: (responsePath: string) => Promise<StatsCommandResponse>;
   removeDir: (targetPath: string) => void;
 };
@@ -37,8 +31,6 @@ const defaultDeps: StatsCommandDeps = {
   joinPath: (...parts) => path.join(...parts),
   runAppCommandAttached: (appPath, appArgs, logLevel, label) =>
     runAppCommandAttached(appPath, appArgs, logLevel, label),
-  launchAppCommandDetached: (appPath, appArgs, logLevel, label) =>
-    launchAppCommandDetached(appPath, appArgs, logLevel, label),
   waitForStatsResponse: async (responsePath) => {
     const deadline = Date.now() + STATS_STARTUP_RESPONSE_TIMEOUT_MS;
     while (Date.now() < deadline) {
@@ -75,12 +67,15 @@ export async function runStatsCommand(
   const responsePath = resolvedDeps.joinPath(tempDir, 'response.json');
 
   try {
-    const forwarded = ['--stats', '--stats-response-path', responsePath];
+    const forwarded = args.statsCleanup
-    if (args.statsBackground) {
+      ? ['--stats', '--stats-response-path', responsePath]
-      forwarded.push('--stats-background');
+      : [
-    }
+          args.statsStop ? '--stats-daemon-stop' : '--stats-daemon-start',
-    if (args.statsStop) {
+          '--stats-response-path',
-      forwarded.push('--stats-stop');
+          responsePath,
+        ];
+    if (!args.statsCleanup && !args.statsBackground && !args.statsStop) {
+      forwarded.push('--stats-daemon-open-browser');
     }
     if (args.statsCleanup) {
       forwarded.push('--stats-cleanup');
@@ -94,14 +89,6 @@ export async function runStatsCommand(
     if (args.logLevel !== 'info') {
       forwarded.push('--log-level', args.logLevel);
     }
-    if (args.statsBackground) {
-      resolvedDeps.launchAppCommandDetached(appPath, forwarded, args.logLevel, 'stats');
-      const startupResult = await resolvedDeps.waitForStatsResponse(responsePath);
-      if (!startupResult.ok) {
-        throw new Error(startupResult.error || 'Stats dashboard failed to start.');
-      }
-      return true;
-    }
     const attachedExitPromise = resolvedDeps.runAppCommandAttached(
       appPath,
       forwarded,

launcher/config/cli-parser-builder.ts

@@ -276,6 +276,16 @@ export function parseCliPrograms(
       if (statsBackground && statsStop) {
         throw new Error('Stats background and stop flags cannot be combined.');
       }
+      if (
+        normalizedAction &&
+        normalizedAction !== 'cleanup' &&
+        normalizedAction !== 'rebuild' &&
+        normalizedAction !== 'backfill'
+      ) {
+        throw new Error(
+          'Invalid stats action. Valid values are cleanup, rebuild, or backfill.',
+        );
+      }
       if (normalizedAction && (statsBackground || statsStop)) {
         throw new Error('Stats background and stop flags cannot be combined with stats actions.');
       }

launcher/main.test.ts

@@ -536,7 +536,7 @@ exit 0
       assert.equal(result.status, 0, `stdout:\n${result.stdout}\nstderr:\n${result.stderr}`);
       assert.match(
         fs.readFileSync(capturePath, 'utf8'),
-        /^--stats\n--stats-response-path\n.+\n--log-level\ndebug\n$/,
+        /^--stats-daemon-start\n--stats-response-path\n.+\n--stats-daemon-open-browser\n--log-level\ndebug\n$/,
       );
     });
   },

launcher/mpv.ts

@@ -45,6 +45,8 @@ export function parseMpvArgString(input: string): string[] {
   let inSingleQuote = false;
   let inDoubleQuote = false;
   let escaping = false;
+  const canEscape = (nextChar: string | undefined): boolean =>
+    nextChar === undefined || nextChar === '"' || nextChar === "'" || nextChar === '\\' || /\s/.test(nextChar);
 
   for (let i = 0; i < chars.length; i += 1) {
     const ch = chars[i] || '';
@@ -65,7 +67,11 @@ export function parseMpvArgString(input: string): string[] {
 
     if (inDoubleQuote) {
       if (ch === '\\') {
+        if (canEscape(chars[i + 1])) {
           escaping = true;
+        } else {
+          current += ch;
+        }
         continue;
       }
       if (ch === '"') {
@@ -77,7 +83,11 @@ export function parseMpvArgString(input: string): string[] {
     }
 
     if (ch === '\\') {
+      if (canEscape(chars[i + 1])) {
         escaping = true;
+      } else {
+        current += ch;
+      }
       continue;
     }
     if (ch === "'") {
@@ -857,8 +867,14 @@ export function runAppCommandAttached(
     proc.once('error', (error) => {
       reject(error);
     });
-    proc.once('exit', (code) => {
+    proc.once('exit', (code, signal) => {
-      resolve(code ?? 0);
+      if (code !== null) {
+        resolve(code);
+      } else if (signal) {
+        resolve(128);
+      } else {
+        resolve(0);
+      }
     });
   });
 }

src/anki-integration.ts

@@ -40,8 +40,10 @@ import { createLogger } from './logger';
 import {
   createUiFeedbackState,
   beginUpdateProgress,
+  clearUpdateProgress,
   endUpdateProgress,
   showStatusNotification,
+  showUpdateResult,
   withUpdateProgress,
   UiFeedbackState,
 } from './anki-integration/ui-feedback';
@@ -310,6 +312,8 @@ export class AnkiIntegration {
           ),
       },
       showOsdNotification: (text: string) => this.showOsdNotification(text),
+      showUpdateResult: (message: string, success: boolean) =>
+        this.showUpdateResult(message, success),
       showStatusNotification: (message: string) => this.showStatusNotification(message),
       showNotification: (noteId, label, errorSuffix) =>
         this.showNotification(noteId, label, errorSuffix),
@@ -773,6 +777,12 @@ export class AnkiIntegration {
     });
   }
 
+  private clearUpdateProgress(): void {
+    clearUpdateProgress(this.uiFeedbackState, (timer) => {
+      clearInterval(timer);
+    });
+  }
+
   private async withUpdateProgress<T>(
     initialMessage: string,
     action: () => Promise<T>,
@@ -903,7 +913,9 @@ export class AnkiIntegration {
     const type = this.config.behavior?.notificationType || 'osd';
 
     if (type === 'osd' || type === 'both') {
-      this.showOsdNotification(message);
+      this.showUpdateResult(message, true);
+    } else {
+      this.clearUpdateProgress();
     }
 
     if ((type === 'system' || type === 'both') && this.notificationCallback) {
@@ -938,6 +950,21 @@ export class AnkiIntegration {
     }
   }
 
+  private showUpdateResult(message: string, success: boolean): void {
+    showUpdateResult(
+      this.uiFeedbackState,
+      {
+        clearProgressTimer: (timer) => {
+          clearInterval(timer);
+        },
+        showOsdNotification: (text) => {
+          this.showOsdNotification(text);
+        },
+      },
+      { message, success },
+    );
+  }
+
   private mergeFieldValue(existing: string, newValue: string, overwrite: boolean): string {
     if (overwrite || !existing.trim()) {
       return newValue;

src/anki-integration/card-creation.ts

@@ -75,6 +75,7 @@ interface CardCreationDeps {
   client: CardCreationClient;
   mediaGenerator: CardCreationMediaGenerator;
   showOsdNotification: (text: string) => void;
+  showUpdateResult: (message: string, success: boolean) => void;
   showStatusNotification: (message: string) => void;
   showNotification: (noteId: number, label: string | number, errorSuffix?: string) => Promise<void>;
   beginUpdateProgress: (initialMessage: string) => void;
@@ -261,8 +262,7 @@ export class CardCreationService {
 
         if (this.deps.getConfig().media?.generateImage) {
           try {
-            const animatedLeadInSeconds =
+            const animatedLeadInSeconds = await this.deps.getAnimatedImageLeadInSeconds(noteInfo);
-              await this.deps.getAnimatedImageLeadInSeconds(noteInfo);
             const imageFilename = this.generateImageFilename();
             const imageBuffer = await this.generateImageBuffer(
               mpvClient.currentVideoPath,
@@ -420,8 +420,7 @@ export class CardCreationService {
 
         if (this.deps.getConfig().media?.generateImage) {
           try {
-            const animatedLeadInSeconds =
+            const animatedLeadInSeconds = await this.deps.getAnimatedImageLeadInSeconds(noteInfo);
-              await this.deps.getAnimatedImageLeadInSeconds(noteInfo);
             const imageFilename = this.generateImageFilename();
             const imageBuffer = await this.generateImageBuffer(
               mpvClient.currentVideoPath,
@@ -554,7 +553,7 @@ export class CardCreationService {
           this.deps.trackLastAddedNoteId?.(noteId);
         } catch (error) {
           log.error('Failed to create sentence card:', (error as Error).message);
-          this.deps.showOsdNotification(`Sentence card failed: ${(error as Error).message}`);
+          this.deps.showUpdateResult(`Sentence card failed: ${(error as Error).message}`, false);
           return false;
         }
 
@@ -651,7 +650,7 @@ export class CardCreationService {
       });
     } catch (error) {
       log.error('Error creating sentence card:', (error as Error).message);
-      this.deps.showOsdNotification(`Sentence card failed: ${(error as Error).message}`);
+      this.deps.showUpdateResult(`Sentence card failed: ${(error as Error).message}`, false);
       return false;
     }
   }

src/anki-integration/ui-feedback.test.ts

@@ -0,0 +1,67 @@
+import test from 'node:test';
+import assert from 'node:assert/strict';
+import {
+  beginUpdateProgress,
+  createUiFeedbackState,
+  showProgressTick,
+  showUpdateResult,
+} from './ui-feedback';
+
+test('showUpdateResult stops spinner before success notification and suppresses stale ticks', () => {
+  const state = createUiFeedbackState();
+  const osdMessages: string[] = [];
+
+  beginUpdateProgress(state, 'Creating sentence card', () => {
+    showProgressTick(state, (text) => {
+      osdMessages.push(text);
+    });
+  });
+
+  showUpdateResult(
+    state,
+    {
+      clearProgressTimer: (timer) => {
+        clearInterval(timer);
+      },
+      showOsdNotification: (text) => {
+        osdMessages.push(text);
+      },
+    },
+    { success: true, message: 'Updated card: taberu' },
+  );
+
+  showProgressTick(state, (text) => {
+    osdMessages.push(text);
+  });
+
+  assert.deepEqual(osdMessages, ['Creating sentence card |', '✓ Updated card: taberu']);
+});
+
+test('showUpdateResult renders failed updates with an x marker', () => {
+  const state = createUiFeedbackState();
+  const osdMessages: string[] = [];
+
+  beginUpdateProgress(state, 'Creating sentence card', () => {
+    showProgressTick(state, (text) => {
+      osdMessages.push(text);
+    });
+  });
+
+  showUpdateResult(
+    state,
+    {
+      clearProgressTimer: (timer) => {
+        clearInterval(timer);
+      },
+      showOsdNotification: (text) => {
+        osdMessages.push(text);
+      },
+    },
+    { success: false, message: 'Sentence card failed: deck missing' },
+  );
+
+  assert.deepEqual(osdMessages, [
+    'Creating sentence card |',
+    'x Sentence card failed: deck missing',
+  ]);
+});

src/anki-integration/ui-feedback.ts

@@ -7,6 +7,11 @@ export interface UiFeedbackState {
   progressFrame: number;
 }
 
+export interface UiFeedbackResult {
+  success: boolean;
+  message: string;
+}
+
 export interface UiFeedbackNotificationContext {
   getNotificationType: () => string | undefined;
   showOsd: (text: string) => void;
@@ -66,6 +71,15 @@ export function endUpdateProgress(
   state.progressDepth = Math.max(0, state.progressDepth - 1);
   if (state.progressDepth > 0) return;
 
+  clearUpdateProgress(state, clearProgressTimer);
+}
+
+export function clearUpdateProgress(
+  state: UiFeedbackState,
+  clearProgressTimer: (timer: ReturnType<typeof setInterval>) => void,
+): void {
+  state.progressDepth = 0;
+
   if (state.progressTimer) {
     clearProgressTimer(state.progressTimer);
     state.progressTimer = null;
@@ -85,6 +99,19 @@ export function showProgressTick(
   showOsdNotification(`${state.progressMessage} ${frame}`);
 }
 
+export function showUpdateResult(
+  state: UiFeedbackState,
+  options: {
+    clearProgressTimer: (timer: ReturnType<typeof setInterval>) => void;
+    showOsdNotification: (text: string) => void;
+  },
+  result: UiFeedbackResult,
+): void {
+  clearUpdateProgress(state, options.clearProgressTimer);
+  const prefix = result.success ? '✓' : 'x';
+  options.showOsdNotification(`${prefix} ${result.message}`);
+}
+
 export async function withUpdateProgress<T>(
   state: UiFeedbackState,
   options: UiFeedbackOptions,

src/core/services/subtitle-ws.test.ts

@@ -130,6 +130,30 @@ test('serializeSubtitleMarkup preserves tooltip attrs and name-match precedence'
   assert.doesNotMatch(markup, /data-frequency-rank="12"|data-jlpt-level="N5"|word-jlpt-n5/);
 });
 
+test('serializeSubtitleMarkup keeps filtered tokens hoverable without annotation attrs', () => {
+  const payload: SubtitleData = {
+    text: 'は',
+    tokens: [
+      {
+        surface: 'は',
+        reading: 'は',
+        headword: 'は',
+        startPos: 0,
+        endPos: 1,
+        partOfSpeech: PartOfSpeech.particle,
+        pos1: '助詞',
+        isMerged: false,
+        isKnown: false,
+        isNPlusOneTarget: false,
+        isNameMatch: false,
+      },
+    ],
+  };
+
+  const markup = serializeSubtitleMarkup(payload, frequencyOptions);
+  assert.equal(markup, '<span class="word" data-reading="は" data-headword="は">は</span>');
+});
+
 test('serializeSubtitleWebsocketMessage emits sentence payload', () => {
   const payload: SubtitleData = {
     text: '字幕',

src/core/services/tokenizer.test.ts

@@ -1305,7 +1305,7 @@ test('tokenizeSubtitle ignores frequency lookup failures', async () => {
   assert.equal(result.tokens?.[0]?.frequencyRank, undefined);
 });
 
-test('tokenizeSubtitle skips frequency rank when Yomitan token is enriched as particle by mecab pos1', async () => {
+test('tokenizeSubtitle keeps standalone particle token hoverable while clearing annotation metadata', async () => {
   const result = await tokenizeSubtitle(
     'は',
     makeDeps({
@@ -1350,9 +1350,33 @@ test('tokenizeSubtitle skips frequency rank when Yomitan token is enriched as pa
     }),
   );
 
-  assert.equal(result.tokens?.length, 1);
+  assert.equal(result.text, 'は');
-  assert.equal(result.tokens?.[0]?.pos1, '助詞');
+  assert.deepEqual(
-  assert.equal(result.tokens?.[0]?.frequencyRank, undefined);
+    result.tokens?.map((token) => ({
+      surface: token.surface,
+      reading: token.reading,
+      headword: token.headword,
+      pos1: token.pos1,
+      isKnown: token.isKnown,
+      isNPlusOneTarget: token.isNPlusOneTarget,
+      isNameMatch: token.isNameMatch,
+      jlptLevel: token.jlptLevel,
+      frequencyRank: token.frequencyRank,
+    })),
+    [
+      {
+        surface: 'は',
+        reading: 'は',
+        headword: 'は',
+        pos1: '助詞',
+        isKnown: false,
+        isNPlusOneTarget: false,
+        isNameMatch: false,
+        jlptLevel: undefined,
+        frequencyRank: undefined,
+      },
+    ],
+  );
 });
 
 test('tokenizeSubtitle keeps frequency rank when mecab tags classify token as content-bearing', async () => {
@@ -1460,7 +1484,7 @@ test('tokenizeSubtitle skips JLPT level for excluded demonstratives', async () =
   assert.equal(result.tokens?.[0]?.jlptLevel, undefined);
 });
 
-test('tokenizeSubtitle excludes repeated kana interjections from annotation payloads entirely', async () => {
+test('tokenizeSubtitle keeps repeated kana interjections tokenized while clearing annotation metadata', async () => {
   const result = await tokenizeSubtitle(
     'ああ',
     makeDeps({
@@ -1491,7 +1515,29 @@ test('tokenizeSubtitle excludes repeated kana interjections from annotation payl
     }),
   );
 
-  assert.deepEqual(result, { text: 'ああ', tokens: null });
+  assert.equal(result.text, 'ああ');
+  assert.deepEqual(
+    result.tokens?.map((token) => ({
+      surface: token.surface,
+      headword: token.headword,
+      reading: token.reading,
+      jlptLevel: token.jlptLevel,
+      frequencyRank: token.frequencyRank,
+      isKnown: token.isKnown,
+      isNPlusOneTarget: token.isNPlusOneTarget,
+    })),
+    [
+      {
+        surface: 'ああ',
+        headword: 'ああ',
+        reading: 'ああ',
+        jlptLevel: undefined,
+        frequencyRank: undefined,
+        isKnown: false,
+        isNPlusOneTarget: false,
+      },
+    ],
+  );
 });
 
 test('tokenizeSubtitle assigns JLPT level to Yomitan tokens', async () => {
@@ -2578,7 +2624,15 @@ test('tokenizeSubtitle keeps correct MeCab pos1 enrichment when Yomitan offsets
   const gaToken = result.tokens?.find((token) => token.surface === 'が');
   const desuToken = result.tokens?.find((token) => token.surface === 'です');
   assert.equal(gaToken?.pos1, '助詞');
+  assert.equal(gaToken?.isKnown, false);
+  assert.equal(gaToken?.isNPlusOneTarget, false);
+  assert.equal(gaToken?.jlptLevel, undefined);
+  assert.equal(gaToken?.frequencyRank, undefined);
   assert.equal(desuToken?.pos1, '助動詞');
+  assert.equal(desuToken?.isKnown, false);
+  assert.equal(desuToken?.isNPlusOneTarget, false);
+  assert.equal(desuToken?.jlptLevel, undefined);
+  assert.equal(desuToken?.frequencyRank, undefined);
   assert.equal(targets.length, 1);
   assert.equal(targets[0]?.surface, '仮面');
 });
@@ -3056,7 +3110,7 @@ test('tokenizeSubtitle excludes default non-independent pos2 from N+1 and freque
   assert.equal(result.tokens?.[0]?.isNPlusOneTarget, false);
 });
 
-test('tokenizeSubtitle excludes mecab-tagged interjections from annotation payloads entirely', async () => {
+test('tokenizeSubtitle keeps mecab-tagged interjections tokenized while clearing annotation metadata', async () => {
   const result = await tokenizeSubtitle(
     'ぐはっ',
     makeDepsFromYomitanTokens([{ surface: 'ぐはっ', reading: 'ぐはっ', headword: 'ぐはっ' }], {
@@ -3080,10 +3134,34 @@ test('tokenizeSubtitle excludes mecab-tagged interjections from annotation paylo
     }),
   );
 
-  assert.deepEqual(result, { text: 'ぐはっ', tokens: null });
+  assert.equal(result.text, 'ぐはっ');
+  assert.deepEqual(
+    result.tokens?.map((token) => ({
+      surface: token.surface,
+      headword: token.headword,
+      reading: token.reading,
+      pos1: token.pos1,
+      jlptLevel: token.jlptLevel,
+      frequencyRank: token.frequencyRank,
+      isKnown: token.isKnown,
+      isNPlusOneTarget: token.isNPlusOneTarget,
+    })),
+    [
+      {
+        surface: 'ぐはっ',
+        headword: 'ぐはっ',
+        reading: 'ぐはっ',
+        pos1: '感動詞',
+        jlptLevel: undefined,
+        frequencyRank: undefined,
+        isKnown: false,
+        isNPlusOneTarget: false,
+      },
+    ],
+  );
 });
 
-test('tokenizeSubtitle keeps visible text while excluding interjections from mixed annotation payloads', async () => {
+test('tokenizeSubtitle keeps excluded interjections hoverable while clearing only their annotation metadata', async () => {
   const result = await tokenizeSubtitle(
     'ぐはっ 猫',
     makeDeps({
@@ -3147,8 +3225,261 @@ test('tokenizeSubtitle keeps visible text while excluding interjections from mix
     result.tokens?.map((token) => ({
       surface: token.surface,
       headword: token.headword,
+      frequencyRank: token.frequencyRank,
+      jlptLevel: token.jlptLevel,
     })),
-    [{ surface: '猫', headword: '猫' }],
+    [
+      { surface: 'ぐはっ', headword: 'ぐはっ', frequencyRank: undefined, jlptLevel: undefined },
+      { surface: '猫', headword: '猫', frequencyRank: 11, jlptLevel: 'N5' },
+    ],
+  );
+});
+
+test('tokenizeSubtitle keeps explanatory ending variants hoverable while clearing only their annotation metadata', async () => {
+  const result = await tokenizeSubtitle(
+    '猫んです',
+    makeDepsFromYomitanTokens(
+      [
+        { surface: '猫', reading: 'ねこ', headword: '猫' },
+        { surface: 'んです', reading: 'んです', headword: 'ん' },
+      ],
+      {
+        getFrequencyDictionaryEnabled: () => true,
+        getFrequencyRank: (text) => (text === '猫' ? 11 : 500),
+        getJlptLevel: (text) => (text === '猫' ? 'N5' : null),
+        tokenizeWithMecab: async () => [
+          {
+            headword: '猫',
+            surface: '猫',
+            reading: 'ネコ',
+            startPos: 0,
+            endPos: 1,
+            partOfSpeech: PartOfSpeech.noun,
+            pos1: '名詞',
+            pos2: '一般',
+            isMerged: false,
+            isKnown: false,
+            isNPlusOneTarget: false,
+          },
+          {
+            headword: 'ん',
+            surface: 'ん',
+            reading: 'ン',
+            startPos: 1,
+            endPos: 2,
+            partOfSpeech: PartOfSpeech.other,
+            pos1: '名詞',
+            pos2: '非自立',
+            isMerged: false,
+            isKnown: false,
+            isNPlusOneTarget: false,
+          },
+          {
+            headword: 'です',
+            surface: 'です',
+            reading: 'デス',
+            startPos: 2,
+            endPos: 4,
+            partOfSpeech: PartOfSpeech.bound_auxiliary,
+            pos1: '助動詞',
+            isMerged: false,
+            isKnown: false,
+            isNPlusOneTarget: false,
+          },
+        ],
+      },
+    ),
+  );
+
+  assert.equal(result.text, '猫んです');
+  assert.deepEqual(
+    result.tokens?.map((token) => ({
+      surface: token.surface,
+      headword: token.headword,
+      jlptLevel: token.jlptLevel,
+      frequencyRank: token.frequencyRank,
+    })),
+    [
+      { surface: '猫', headword: '猫', jlptLevel: 'N5', frequencyRank: 11 },
+      { surface: 'んです', headword: 'ん', jlptLevel: undefined, frequencyRank: undefined },
+    ],
+  );
+});
+
+test('tokenizeSubtitle keeps standalone grammar-only tokens hoverable while clearing only their annotation metadata', async () => {
+  const result = await tokenizeSubtitle(
+    '私はこの猫です',
+    makeDeps({
+      getFrequencyDictionaryEnabled: () => true,
+      getFrequencyRank: (text) => (text === '私' ? 50 : text === '猫' ? 11 : 500),
+      getJlptLevel: (text) => (text === '私' ? 'N5' : text === '猫' ? 'N5' : null),
+      getYomitanExt: () => ({ id: 'dummy-ext' }) as any,
+      getYomitanParserWindow: () =>
+        ({
+          isDestroyed: () => false,
+          webContents: {
+            executeJavaScript: async (script: string) => {
+              if (script.includes('getTermFrequencies')) {
+                return [];
+              }
+
+              return [
+                {
+                  source: 'scanning-parser',
+                  index: 0,
+                  content: [
+                    [{ text: '私', reading: 'わたし', headwords: [[{ term: '私' }]] }],
+                    [{ text: 'は', reading: 'は', headwords: [[{ term: 'は' }]] }],
+                    [{ text: 'この', reading: 'この', headwords: [[{ term: 'この' }]] }],
+                    [{ text: '猫', reading: 'ねこ', headwords: [[{ term: '猫' }]] }],
+                    [{ text: 'です', reading: 'です', headwords: [[{ term: 'です' }]] }],
+                  ],
+                },
+              ];
+            },
+          },
+        }) as unknown as Electron.BrowserWindow,
+      tokenizeWithMecab: async () => [
+        {
+          headword: '私',
+          surface: '私',
+          reading: 'ワタシ',
+          startPos: 0,
+          endPos: 1,
+          partOfSpeech: PartOfSpeech.noun,
+          pos1: '名詞',
+          pos2: '代名詞',
+          isMerged: true,
+          isKnown: false,
+          isNPlusOneTarget: false,
+        },
+        {
+          headword: 'は',
+          surface: 'は',
+          reading: 'ハ',
+          startPos: 1,
+          endPos: 2,
+          partOfSpeech: PartOfSpeech.particle,
+          pos1: '助詞',
+          pos2: '係助詞',
+          isMerged: true,
+          isKnown: false,
+          isNPlusOneTarget: false,
+        },
+        {
+          headword: 'この',
+          surface: 'この',
+          reading: 'コノ',
+          startPos: 2,
+          endPos: 4,
+          partOfSpeech: PartOfSpeech.other,
+          pos1: '連体詞',
+          isMerged: true,
+          isKnown: false,
+          isNPlusOneTarget: false,
+        },
+        {
+          headword: '猫',
+          surface: '猫',
+          reading: 'ネコ',
+          startPos: 4,
+          endPos: 5,
+          partOfSpeech: PartOfSpeech.noun,
+          pos1: '名詞',
+          pos2: '一般',
+          isMerged: true,
+          isKnown: false,
+          isNPlusOneTarget: false,
+        },
+        {
+          headword: 'です',
+          surface: 'です',
+          reading: 'デス',
+          startPos: 5,
+          endPos: 7,
+          partOfSpeech: PartOfSpeech.bound_auxiliary,
+          pos1: '助動詞',
+          isMerged: true,
+          isKnown: false,
+          isNPlusOneTarget: false,
+        },
+      ],
+    }),
+  );
+
+  assert.equal(result.text, '私はこの猫です');
+  assert.deepEqual(
+    result.tokens?.map((token) => ({
+      surface: token.surface,
+      headword: token.headword,
+      frequencyRank: token.frequencyRank,
+      jlptLevel: token.jlptLevel,
+    })),
+    [
+      { surface: '私', headword: '私', frequencyRank: 50, jlptLevel: 'N5' },
+      { surface: 'は', headword: 'は', frequencyRank: undefined, jlptLevel: undefined },
+      { surface: 'この', headword: 'この', frequencyRank: undefined, jlptLevel: undefined },
+      { surface: '猫', headword: '猫', frequencyRank: 11, jlptLevel: 'N5' },
+      { surface: 'です', headword: 'です', frequencyRank: undefined, jlptLevel: undefined },
+    ],
+  );
+});
+
+test('tokenizeSubtitle keeps trailing quote-particle merged tokens hoverable while clearing only their annotation metadata', async () => {
+  const result = await tokenizeSubtitle(
+    'どうしてもって',
+    makeDepsFromYomitanTokens([{ surface: 'どうしてもって', reading: 'どうしてもって', headword: 'どうしても' }], {
+      getFrequencyDictionaryEnabled: () => true,
+      getFrequencyRank: (text) => (text === 'どうしても' ? 123 : null),
+      getJlptLevel: (text) => (text === 'どうしても' ? 'N3' : null),
+      tokenizeWithMecab: async () => [
+        {
+          headword: 'どうしても',
+          surface: 'どうしても',
+          reading: 'ドウシテモ',
+          startPos: 0,
+          endPos: 5,
+          partOfSpeech: PartOfSpeech.other,
+          pos1: '副詞',
+          pos2: '一般',
+          isMerged: false,
+          isKnown: false,
+          isNPlusOneTarget: false,
+        },
+        {
+          headword: 'って',
+          surface: 'って',
+          reading: 'ッテ',
+          startPos: 5,
+          endPos: 7,
+          partOfSpeech: PartOfSpeech.particle,
+          pos1: '助詞',
+          pos2: '格助詞',
+          isMerged: false,
+          isKnown: false,
+          isNPlusOneTarget: false,
+        },
+      ],
+      getMinSentenceWordsForNPlusOne: () => 1,
+    }),
+  );
+
+  assert.equal(result.text, 'どうしてもって');
+  assert.deepEqual(
+    result.tokens?.map((token) => ({
+      surface: token.surface,
+      headword: token.headword,
+      jlptLevel: token.jlptLevel,
+      frequencyRank: token.frequencyRank,
+    })),
+    [
+      {
+        surface: 'どうしてもって',
+        headword: 'どうしても',
+        jlptLevel: undefined,
+        frequencyRank: undefined,
+      },
+    ],
   );
 });
 

src/core/services/tokenizer.ts

@@ -178,7 +178,7 @@ async function applyAnnotationStage(
   );
 }
 
-async function filterSubtitleAnnotationTokens(tokens: MergedToken[]): Promise<MergedToken[]> {
+async function stripSubtitleAnnotationMetadata(tokens: MergedToken[]): Promise<MergedToken[]> {
   if (tokens.length === 0) {
     return tokens;
   }
@@ -188,9 +188,7 @@ async function filterSubtitleAnnotationTokens(tokens: MergedToken[]): Promise<Me
   }
 
   const annotationStage = await annotationStageModulePromise;
-  return tokens.filter(
+  return tokens.map((token) => annotationStage.stripSubtitleAnnotationMetadata(token));
-    (token) => !annotationStage.shouldExcludeTokenFromSubtitleAnnotations(token),
-  );
 }
 
 export function createTokenizerDepsRuntime(
@@ -721,12 +719,12 @@ export async function tokenizeSubtitle(
 
   const yomitanTokens = await parseWithYomitanInternalParser(tokenizeText, deps, annotationOptions);
   if (yomitanTokens && yomitanTokens.length > 0) {
-    const filteredTokens = await filterSubtitleAnnotationTokens(
+    const annotatedTokens = await stripSubtitleAnnotationMetadata(
       await applyAnnotationStage(yomitanTokens, deps, annotationOptions),
     );
     return {
       text: displayText,
-      tokens: filteredTokens.length > 0 ? filteredTokens : null,
+      tokens: annotatedTokens.length > 0 ? annotatedTokens : null,
     };
   }
 

src/core/services/tokenizer/annotation-stage.test.ts

@@ -1,7 +1,12 @@
 import assert from 'node:assert/strict';
 import test from 'node:test';
 import { MergedToken, PartOfSpeech } from '../../../types';
-import { annotateTokens, AnnotationStageDeps } from './annotation-stage';
+import {
+  annotateTokens,
+  AnnotationStageDeps,
+  shouldExcludeTokenFromSubtitleAnnotations,
+  stripSubtitleAnnotationMetadata,
+} from './annotation-stage';
 
 function makeToken(overrides: Partial<MergedToken> = {}): MergedToken {
   return {
@@ -150,6 +155,170 @@ test('annotateTokens handles JLPT disabled and eligibility exclusion paths', ()
   assert.equal(excludedLookupCalls, 0);
 });
 
+test('shouldExcludeTokenFromSubtitleAnnotations excludes explanatory ending variants', () => {
+  const tokens = [
+    makeToken({
+      surface: 'んです',
+      headword: 'ん',
+      reading: 'ンデス',
+      pos1: '名詞|助動詞',
+      pos2: '非自立',
+    }),
+    makeToken({
+      surface: 'のだ',
+      headword: 'の',
+      reading: 'ノダ',
+      pos1: '名詞|助動詞',
+      pos2: '非自立',
+    }),
+    makeToken({
+      surface: 'んだ',
+      headword: 'ん',
+      reading: 'ンダ',
+      pos1: '名詞|助動詞',
+      pos2: '非自立',
+    }),
+    makeToken({
+      surface: 'のです',
+      headword: 'の',
+      reading: 'ノデス',
+      pos1: '名詞|助動詞',
+      pos2: '非自立',
+    }),
+    makeToken({
+      surface: 'なんです',
+      headword: 'だ',
+      reading: 'ナンデス',
+      pos1: '助動詞|名詞|助動詞',
+      pos2: '|非自立',
+    }),
+    makeToken({
+      surface: 'んでした',
+      headword: 'ん',
+      reading: 'ンデシタ',
+      pos1: '助動詞|助動詞|助動詞',
+    }),
+    makeToken({
+      surface: 'のでは',
+      headword: 'の',
+      reading: 'ノデハ',
+      pos1: '助詞|接続詞',
+    }),
+  ];
+
+  for (const token of tokens) {
+    assert.equal(shouldExcludeTokenFromSubtitleAnnotations(token), true, token.surface);
+  }
+});
+
+test('shouldExcludeTokenFromSubtitleAnnotations keeps lexical tokens outside explanatory ending family', () => {
+  const token = makeToken({
+    surface: '問題',
+    headword: '問題',
+    reading: 'モンダイ',
+    partOfSpeech: PartOfSpeech.noun,
+    pos1: '名詞',
+    pos2: '一般',
+  });
+
+  assert.equal(shouldExcludeTokenFromSubtitleAnnotations(token), false);
+});
+
+test('shouldExcludeTokenFromSubtitleAnnotations excludes standalone particles auxiliaries and adnominals', () => {
+  const tokens = [
+    makeToken({
+      surface: 'は',
+      headword: 'は',
+      reading: 'ハ',
+      partOfSpeech: PartOfSpeech.particle,
+      pos1: '助詞',
+    }),
+    makeToken({
+      surface: 'です',
+      headword: 'です',
+      reading: 'デス',
+      partOfSpeech: PartOfSpeech.bound_auxiliary,
+      pos1: '助動詞',
+    }),
+    makeToken({
+      surface: 'この',
+      headword: 'この',
+      reading: 'コノ',
+      partOfSpeech: PartOfSpeech.other,
+      pos1: '連体詞',
+    }),
+  ];
+
+  for (const token of tokens) {
+    assert.equal(shouldExcludeTokenFromSubtitleAnnotations(token), true, token.surface);
+  }
+});
+
+test('shouldExcludeTokenFromSubtitleAnnotations keeps mixed content tokens with trailing helpers', () => {
+  const token = makeToken({
+    surface: '行きます',
+    headword: '行く',
+    reading: 'イキマス',
+    partOfSpeech: PartOfSpeech.verb,
+    pos1: '動詞|助動詞',
+    pos2: '自立',
+  });
+
+  assert.equal(shouldExcludeTokenFromSubtitleAnnotations(token), false);
+});
+
+test('shouldExcludeTokenFromSubtitleAnnotations excludes merged lexical tokens with trailing quote particles', () => {
+  const token = makeToken({
+    surface: 'どうしてもって',
+    headword: 'どうしても',
+    reading: 'ドウシテモッテ',
+    partOfSpeech: PartOfSpeech.other,
+    pos1: '副詞|助詞',
+    pos2: '一般|格助詞',
+  });
+
+  assert.equal(shouldExcludeTokenFromSubtitleAnnotations(token), true);
+});
+
+test('stripSubtitleAnnotationMetadata keeps token hover data while clearing annotation fields', () => {
+  const token = makeToken({
+    surface: 'は',
+    headword: 'は',
+    reading: 'ハ',
+    partOfSpeech: PartOfSpeech.particle,
+    pos1: '助詞',
+    isKnown: true,
+    isNPlusOneTarget: true,
+    isNameMatch: true,
+    jlptLevel: 'N5',
+    frequencyRank: 12,
+  });
+
+  assert.deepEqual(stripSubtitleAnnotationMetadata(token), {
+    ...token,
+    isKnown: false,
+    isNPlusOneTarget: false,
+    isNameMatch: false,
+    jlptLevel: undefined,
+    frequencyRank: undefined,
+  });
+});
+
+test('stripSubtitleAnnotationMetadata leaves content tokens unchanged', () => {
+  const token = makeToken({
+    surface: '猫',
+    headword: '猫',
+    reading: 'ネコ',
+    partOfSpeech: PartOfSpeech.noun,
+    pos1: '名詞',
+    isKnown: true,
+    jlptLevel: 'N5',
+    frequencyRank: 42,
+  });
+
+  assert.strictEqual(stripSubtitleAnnotationMetadata(token), token);
+});
+
 test('annotateTokens prioritizes name matches over n+1, frequency, and JLPT when enabled', () => {
   let jlptLookupCalls = 0;
   const tokens = [

src/core/services/tokenizer/annotation-stage.ts

@@ -25,6 +25,45 @@ const SUBTITLE_ANNOTATION_EXCLUDED_TERMS = new Set([
   'ふう',
   'ほう',
 ]);
+const SUBTITLE_ANNOTATION_EXCLUDED_EXPLANATORY_ENDING_PREFIXES = ['ん', 'の', 'なん', 'なの'];
+const SUBTITLE_ANNOTATION_EXCLUDED_EXPLANATORY_ENDING_CORES = [
+  'だ',
+  'です',
+  'でした',
+  'だった',
+  'では',
+  'じゃ',
+  'でしょう',
+  'だろう',
+] as const;
+const SUBTITLE_ANNOTATION_EXCLUDED_EXPLANATORY_ENDING_TRAILING_PARTICLES = [
+  '',
+  'か',
+  'ね',
+  'よ',
+  'な',
+  'よね',
+  'かな',
+  'かね',
+] as const;
+const SUBTITLE_ANNOTATION_EXCLUDED_EXPLANATORY_ENDINGS = new Set(
+  SUBTITLE_ANNOTATION_EXCLUDED_EXPLANATORY_ENDING_PREFIXES.flatMap((prefix) =>
+    SUBTITLE_ANNOTATION_EXCLUDED_EXPLANATORY_ENDING_CORES.flatMap((core) =>
+      SUBTITLE_ANNOTATION_EXCLUDED_EXPLANATORY_ENDING_TRAILING_PARTICLES.map(
+        (particle) => `${prefix}${core}${particle}`,
+      ),
+    ),
+  ),
+);
+const SUBTITLE_ANNOTATION_EXCLUDED_TRAILING_PARTICLE_SUFFIXES = new Set([
+  'って',
+  'ってよ',
+  'ってね',
+  'ってな',
+  'ってさ',
+  'ってか',
+  'ってば',
+]);
 
 const jlptLevelLookupCaches = new WeakMap<
   (text: string) => JlptLevel | null,
@@ -60,6 +99,7 @@ function normalizePos1Tag(pos1: string | undefined): string {
 }
 
 const SUBTITLE_ANNOTATION_EXCLUDED_POS1 = new Set(['感動詞']);
+const SUBTITLE_ANNOTATION_GRAMMAR_ONLY_POS1 = new Set(['助詞', '助動詞', '連体詞']);
 
 function splitNormalizedTagParts(normalizedTag: string): string[] {
   if (!normalizedTag) {
@@ -84,7 +124,36 @@ function isExcludedByTagSet(normalizedTag: string, exclusions: ReadonlySet<strin
 
 function isExcludedFromSubtitleAnnotationsByPos1(normalizedPos1: string): boolean {
   const parts = splitNormalizedTagParts(normalizedPos1);
-  return parts.some((part) => SUBTITLE_ANNOTATION_EXCLUDED_POS1.has(part));
+  if (parts.some((part) => SUBTITLE_ANNOTATION_EXCLUDED_POS1.has(part))) {
+    return true;
+  }
+
+  return parts.length > 0 && parts.every((part) => SUBTITLE_ANNOTATION_GRAMMAR_ONLY_POS1.has(part));
+}
+
+function isExcludedTrailingParticleMergedToken(token: MergedToken): boolean {
+  const normalizedSurface = normalizeJlptTextForExclusion(token.surface);
+  const normalizedHeadword = normalizeJlptTextForExclusion(token.headword);
+  if (!normalizedSurface || !normalizedHeadword || !normalizedSurface.startsWith(normalizedHeadword)) {
+    return false;
+  }
+
+  const suffix = normalizedSurface.slice(normalizedHeadword.length);
+  if (!SUBTITLE_ANNOTATION_EXCLUDED_TRAILING_PARTICLE_SUFFIXES.has(suffix)) {
+    return false;
+  }
+
+  const pos1Parts = splitNormalizedTagParts(normalizePos1Tag(token.pos1));
+  if (pos1Parts.length < 2) {
+    return false;
+  }
+
+  const [leadingPos1, ...trailingPos1] = pos1Parts;
+  if (!leadingPos1 || SUBTITLE_ANNOTATION_GRAMMAR_ONLY_POS1.has(leadingPos1)) {
+    return false;
+  }
+
+  return trailingPos1.length > 0 && trailingPos1.every((part) => part === '助詞');
 }
 
 function resolvePos1Exclusions(options: AnnotationStageOptions): ReadonlySet<string> {
@@ -520,12 +589,7 @@ function isJlptEligibleToken(token: MergedToken): boolean {
 }
 
 function isExcludedFromSubtitleAnnotationsByTerm(token: MergedToken): boolean {
-  const candidates = [
+  const candidates = [token.surface, token.reading, resolveJlptLookupText(token)].filter(
-    resolveJlptLookupText(token),
-    token.surface,
-    token.headword,
-    token.reading,
-  ].filter(
     (candidate): candidate is string => typeof candidate === 'string' && candidate.length > 0,
   );
 
@@ -542,7 +606,9 @@ function isExcludedFromSubtitleAnnotationsByTerm(token: MergedToken): boolean {
 
     if (
       SUBTITLE_ANNOTATION_EXCLUDED_TERMS.has(trimmedCandidate) ||
-      SUBTITLE_ANNOTATION_EXCLUDED_TERMS.has(normalizedCandidate)
+      SUBTITLE_ANNOTATION_EXCLUDED_TERMS.has(normalizedCandidate) ||
+      SUBTITLE_ANNOTATION_EXCLUDED_EXPLANATORY_ENDINGS.has(trimmedCandidate) ||
+      SUBTITLE_ANNOTATION_EXCLUDED_EXPLANATORY_ENDINGS.has(normalizedCandidate)
     ) {
       return true;
     }
@@ -565,9 +631,28 @@ export function shouldExcludeTokenFromSubtitleAnnotations(token: MergedToken): b
     return true;
   }
 
+  if (isExcludedTrailingParticleMergedToken(token)) {
+    return true;
+  }
+
   return isExcludedFromSubtitleAnnotationsByTerm(token);
 }
 
+export function stripSubtitleAnnotationMetadata(token: MergedToken): MergedToken {
+  if (!shouldExcludeTokenFromSubtitleAnnotations(token)) {
+    return token;
+  }
+
+  return {
+    ...token,
+    isKnown: false,
+    isNPlusOneTarget: false,
+    isNameMatch: false,
+    jlptLevel: undefined,
+    frequencyRank: undefined,
+  };
+}
+
 function computeTokenKnownStatus(
   token: MergedToken,
   isKnownWord: (text: string) => boolean,

src/main-entry-runtime.test.ts

@@ -11,6 +11,7 @@ import {
   shouldDetachBackgroundLaunch,
   shouldHandleHelpOnlyAtEntry,
   shouldHandleLaunchMpvAtEntry,
+  shouldHandleStatsDaemonCommandAtEntry,
 } from './main-entry-runtime';
 
 test('normalizeStartupArgv defaults no-arg startup to --start --background on non-Windows', () => {
@@ -71,6 +72,25 @@ test('launch-mpv entry helpers detect and normalize targets', () => {
   ]);
 });
 
+test('stats-daemon entry helper detects internal daemon commands', () => {
+  assert.equal(
+    shouldHandleStatsDaemonCommandAtEntry(['SubMiner.AppImage', '--stats-daemon-start'], {}),
+    true,
+  );
+  assert.equal(
+    shouldHandleStatsDaemonCommandAtEntry(['SubMiner.AppImage', '--stats-daemon-stop'], {}),
+    true,
+  );
+  assert.equal(
+    shouldHandleStatsDaemonCommandAtEntry(
+      ['SubMiner.AppImage', '--stats-daemon-start'],
+      { ELECTRON_RUN_AS_NODE: '1' },
+    ),
+    false,
+  );
+  assert.equal(shouldHandleStatsDaemonCommandAtEntry(['SubMiner.AppImage', '--start'], {}), false);
+});
+
 test('sanitizeStartupEnv suppresses warnings and lsfg layer', () => {
   const env = sanitizeStartupEnv({
     VK_INSTANCE_LAYERS: 'foo:lsfg-vk:bar',

src/main-entry-runtime.ts

@@ -112,6 +112,14 @@ export function shouldHandleLaunchMpvAtEntry(argv: string[], env: NodeJS.Process
   return parseCliArgs(argv).launchMpv;
 }
 
+export function shouldHandleStatsDaemonCommandAtEntry(
+  argv: string[],
+  env: NodeJS.ProcessEnv,
+): boolean {
+  if (env.ELECTRON_RUN_AS_NODE === '1') return false;
+  return argv.includes('--stats-daemon-start') || argv.includes('--stats-daemon-stop');
+}
+
 export function normalizeLaunchMpvTargets(argv: string[]): string[] {
   return parseCliArgs(argv).launchMpvTargets;
 }

src/main-entry.ts

@@ -12,9 +12,11 @@ import {
   shouldDetachBackgroundLaunch,
   shouldHandleHelpOnlyAtEntry,
   shouldHandleLaunchMpvAtEntry,
+  shouldHandleStatsDaemonCommandAtEntry,
 } from './main-entry-runtime';
 import { requestSingleInstanceLockEarly } from './main/early-single-instance';
 import { createWindowsMpvLaunchDeps, launchWindowsMpv } from './main/runtime/windows-mpv-launch';
+import { runStatsDaemonControlFromProcess } from './stats-daemon-entry';
 
 const DEFAULT_TEXTHOOKER_PORT = 5174;
 
@@ -69,6 +71,11 @@ if (shouldHandleLaunchMpvAtEntry(process.argv, process.env)) {
     );
     app.exit(result.ok ? 0 : 1);
   });
+} else if (shouldHandleStatsDaemonCommandAtEntry(process.argv, process.env)) {
+  void app.whenReady().then(async () => {
+    const exitCode = await runStatsDaemonControlFromProcess(app.getPath('userData'));
+    app.exit(exitCode);
+  });
 } else {
   const gotSingleInstanceLock = requestSingleInstanceLockEarly(app);
   if (!gotSingleInstanceLock) {

src/renderer/subtitle-render.test.ts

@@ -682,7 +682,7 @@ test('renderSubtitle preserves unsupported punctuation while keeping it non-inte
   }
 });
 
-test('renderSubtitle keeps excluded interjection text visible while only rendering remaining tokens as interactive', () => {
+test('renderSubtitle keeps excluded interjection tokens hoverable while rendering them without annotation styling', () => {
   const restoreDocument = installFakeDocument();
 
   try {
@@ -718,13 +718,19 @@ test('renderSubtitle keeps excluded interjection text visible while only renderi
 
     renderer.renderSubtitle({
       text: 'ぐはっ 猫',
-      tokens: [createToken({ surface: '猫', headword: '猫', reading: 'ねこ' })],
+      tokens: [
+        createToken({ surface: 'ぐはっ', headword: 'ぐはっ', reading: 'ぐはっ' }),
+        createToken({ surface: '猫', headword: '猫', reading: 'ねこ' }),
+      ],
     });
 
     assert.equal(subtitleRoot.textContent, 'ぐはっ 猫');
     assert.deepEqual(
       collectWordNodes(subtitleRoot).map((node) => [node.textContent, node.dataset.tokenIndex]),
-      [['猫', '0']],
+      [
+        ['ぐはっ', '0'],
+        ['猫', '1'],
+      ],
     );
   } finally {
     restoreDocument();

src/stats-daemon-control.test.ts

@@ -0,0 +1,158 @@
+import assert from 'node:assert/strict';
+import test from 'node:test';
+import { createRunStatsDaemonControlHandler } from './stats-daemon-control';
+
+test('stats daemon control reuses live daemon and writes launcher response', async () => {
+  const calls: string[] = [];
+  const responses: Array<{ path: string; payload: { ok: boolean; url?: string; error?: string } }> =
+    [];
+  const handler = createRunStatsDaemonControlHandler({
+    statePath: '/tmp/stats-daemon.json',
+    readState: () => ({ pid: 4242, port: 5175, startedAtMs: 1 }),
+    removeState: () => {
+      calls.push('removeState');
+    },
+    isProcessAlive: (pid) => {
+      calls.push(`isProcessAlive:${pid}`);
+      return true;
+    },
+    resolveUrl: (state) => `http://127.0.0.1:${state.port}`,
+    spawnDaemon: async () => {
+      calls.push('spawnDaemon');
+      return 1;
+    },
+    waitForDaemonResponse: async () => {
+      calls.push('waitForDaemonResponse');
+      return { ok: true, url: 'http://127.0.0.1:5175' };
+    },
+    openExternal: async (url) => {
+      calls.push(`openExternal:${url}`);
+    },
+    writeResponse: (responsePath, payload) => {
+      responses.push({ path: responsePath, payload });
+    },
+    killProcess: () => {
+      calls.push('killProcess');
+    },
+    sleep: async () => {},
+  });
+
+  const exitCode = await handler({
+    action: 'start',
+    responsePath: '/tmp/response.json',
+    openBrowser: true,
+    daemonScriptPath: '/tmp/stats-daemon-runner.js',
+    userDataPath: '/tmp/SubMiner',
+  });
+
+  assert.equal(exitCode, 0);
+  assert.deepEqual(calls, ['isProcessAlive:4242', 'openExternal:http://127.0.0.1:5175']);
+  assert.deepEqual(responses, [
+    {
+      path: '/tmp/response.json',
+      payload: { ok: true, url: 'http://127.0.0.1:5175' },
+    },
+  ]);
+});
+
+test('stats daemon control clears stale state, starts daemon, and waits for response', async () => {
+  const calls: string[] = [];
+  const handler = createRunStatsDaemonControlHandler({
+    statePath: '/tmp/stats-daemon.json',
+    readState: () => ({ pid: 4242, port: 5175, startedAtMs: 1 }),
+    removeState: () => {
+      calls.push('removeState');
+    },
+    isProcessAlive: (pid) => {
+      calls.push(`isProcessAlive:${pid}`);
+      return false;
+    },
+    resolveUrl: (state) => `http://127.0.0.1:${state.port}`,
+    spawnDaemon: async (options) => {
+      calls.push(`spawnDaemon:${options.scriptPath}:${options.responsePath}:${options.userDataPath}`);
+      return 999;
+    },
+    waitForDaemonResponse: async (responsePath) => {
+      calls.push(`waitForDaemonResponse:${responsePath}`);
+      return { ok: true, url: 'http://127.0.0.1:5175' };
+    },
+    openExternal: async (url) => {
+      calls.push(`openExternal:${url}`);
+    },
+    writeResponse: () => {
+      calls.push('writeResponse');
+    },
+    killProcess: () => {
+      calls.push('killProcess');
+    },
+    sleep: async () => {},
+  });
+
+  const exitCode = await handler({
+    action: 'start',
+    responsePath: '/tmp/response.json',
+    openBrowser: false,
+    daemonScriptPath: '/tmp/stats-daemon-runner.js',
+    userDataPath: '/tmp/SubMiner',
+  });
+
+  assert.equal(exitCode, 0);
+  assert.deepEqual(calls, [
+    'isProcessAlive:4242',
+    'removeState',
+    'spawnDaemon:/tmp/stats-daemon-runner.js:/tmp/response.json:/tmp/SubMiner',
+    'waitForDaemonResponse:/tmp/response.json',
+  ]);
+});
+
+test('stats daemon control stops live daemon and treats stale state as success', async () => {
+  const responses: Array<{ path: string; payload: { ok: boolean; url?: string; error?: string } }> =
+    [];
+  const calls: string[] = [];
+  let aliveChecks = 0;
+  const handler = createRunStatsDaemonControlHandler({
+    statePath: '/tmp/stats-daemon.json',
+    readState: () => ({ pid: 4242, port: 5175, startedAtMs: 1 }),
+    removeState: () => {
+      calls.push('removeState');
+    },
+    isProcessAlive: (pid) => {
+      aliveChecks += 1;
+      calls.push(`isProcessAlive:${pid}:${aliveChecks}`);
+      return aliveChecks === 1;
+    },
+    resolveUrl: (state) => `http://127.0.0.1:${state.port}`,
+    spawnDaemon: async () => 1,
+    waitForDaemonResponse: async () => ({ ok: true, url: 'http://127.0.0.1:5175' }),
+    openExternal: async () => {},
+    writeResponse: (responsePath, payload) => {
+      responses.push({ path: responsePath, payload });
+    },
+    killProcess: (pid, signal) => {
+      calls.push(`killProcess:${pid}:${signal}`);
+    },
+    sleep: async () => {},
+  });
+
+  const exitCode = await handler({
+    action: 'stop',
+    responsePath: '/tmp/response.json',
+    openBrowser: false,
+    daemonScriptPath: '/tmp/stats-daemon-runner.js',
+    userDataPath: '/tmp/SubMiner',
+  });
+
+  assert.equal(exitCode, 0);
+  assert.deepEqual(calls, [
+    'isProcessAlive:4242:1',
+    'killProcess:4242:SIGTERM',
+    'isProcessAlive:4242:2',
+    'removeState',
+  ]);
+  assert.deepEqual(responses, [
+    {
+      path: '/tmp/response.json',
+      payload: { ok: true },
+    },
+  ]);
+});

src/stats-daemon-control.ts

@@ -0,0 +1,102 @@
+import type { BackgroundStatsServerState } from './main/runtime/stats-daemon';
+import type { StatsCliCommandResponse } from './main/runtime/stats-cli-command';
+
+export type StatsDaemonControlAction = 'start' | 'stop';
+
+export type StatsDaemonControlArgs = {
+  action: StatsDaemonControlAction;
+  responsePath?: string;
+  openBrowser: boolean;
+  daemonScriptPath: string;
+  userDataPath: string;
+};
+
+type SpawnStatsDaemonOptions = {
+  scriptPath: string;
+  responsePath?: string;
+  userDataPath: string;
+};
+
+export function createRunStatsDaemonControlHandler(deps: {
+  statePath: string;
+  readState: () => BackgroundStatsServerState | null;
+  removeState: () => void;
+  isProcessAlive: (pid: number) => boolean;
+  resolveUrl: (state: Pick<BackgroundStatsServerState, 'port'>) => string;
+  spawnDaemon: (options: SpawnStatsDaemonOptions) => Promise<number> | number;
+  waitForDaemonResponse: (responsePath: string) => Promise<StatsCliCommandResponse>;
+  openExternal: (url: string) => Promise<unknown>;
+  writeResponse: (responsePath: string, payload: StatsCliCommandResponse) => void;
+  killProcess: (pid: number, signal: NodeJS.Signals) => void;
+  sleep: (ms: number) => Promise<void>;
+}) {
+  const writeResponseSafe = (
+    responsePath: string | undefined,
+    payload: StatsCliCommandResponse,
+  ): void => {
+    if (!responsePath) return;
+    deps.writeResponse(responsePath, payload);
+  };
+
+  return async (args: StatsDaemonControlArgs): Promise<number> => {
+    if (args.action === 'start') {
+      const state = deps.readState();
+      if (state) {
+        if (deps.isProcessAlive(state.pid)) {
+          const url = deps.resolveUrl(state);
+          writeResponseSafe(args.responsePath, { ok: true, url });
+          if (args.openBrowser) {
+            await deps.openExternal(url);
+          }
+          return 0;
+        }
+        deps.removeState();
+      }
+
+      if (!args.responsePath) {
+        throw new Error('Missing --stats-response-path for stats daemon start.');
+      }
+
+      await deps.spawnDaemon({
+        scriptPath: args.daemonScriptPath,
+        responsePath: args.responsePath,
+        userDataPath: args.userDataPath,
+      });
+      const response = await deps.waitForDaemonResponse(args.responsePath);
+      if (response.ok && args.openBrowser && response.url) {
+        await deps.openExternal(response.url);
+      }
+      return response.ok ? 0 : 1;
+    }
+
+    const state = deps.readState();
+    if (!state) {
+      deps.removeState();
+      writeResponseSafe(args.responsePath, { ok: true });
+      return 0;
+    }
+
+    if (!deps.isProcessAlive(state.pid)) {
+      deps.removeState();
+      writeResponseSafe(args.responsePath, { ok: true });
+      return 0;
+    }
+
+    deps.killProcess(state.pid, 'SIGTERM');
+    const deadline = Date.now() + 2_000;
+    while (Date.now() < deadline) {
+      if (!deps.isProcessAlive(state.pid)) {
+        deps.removeState();
+        writeResponseSafe(args.responsePath, { ok: true });
+        return 0;
+      }
+      await deps.sleep(50);
+    }
+
+    writeResponseSafe(args.responsePath, {
+      ok: false,
+      error: 'Timed out stopping background stats server.',
+    });
+    return 1;
+  };
+}

src/stats-daemon-entry.ts

@@ -0,0 +1,135 @@
+import fs from 'node:fs';
+import path from 'node:path';
+import { spawn } from 'node:child_process';
+import { shell } from 'electron';
+import { sanitizeStartupEnv } from './main-entry-runtime';
+import {
+  isBackgroundStatsServerProcessAlive,
+  readBackgroundStatsServerState,
+  removeBackgroundStatsServerState,
+  resolveBackgroundStatsServerUrl,
+} from './main/runtime/stats-daemon';
+import {
+  createRunStatsDaemonControlHandler,
+  type StatsDaemonControlArgs,
+} from './stats-daemon-control';
+import {
+  type StatsCliCommandResponse,
+  writeStatsCliCommandResponse,
+} from './main/runtime/stats-cli-command';
+
+const STATS_DAEMON_RESPONSE_TIMEOUT_MS = 12_000;
+
+function readFlagValue(argv: string[], flag: string): string | undefined {
+  for (let i = 0; i < argv.length; i += 1) {
+    const arg = argv[i];
+    if (!arg) continue;
+    if (arg === flag) {
+      const value = argv[i + 1];
+      if (value && !value.startsWith('--')) {
+        return value;
+      }
+      return undefined;
+    }
+    if (arg.startsWith(`${flag}=`)) {
+      return arg.split('=', 2)[1];
+    }
+  }
+  return undefined;
+}
+
+function hasFlag(argv: string[], flag: string): boolean {
+  return argv.includes(flag);
+}
+
+function parseControlArgs(argv: string[], userDataPath: string): StatsDaemonControlArgs {
+  return {
+    action: hasFlag(argv, '--stats-daemon-stop') ? 'stop' : 'start',
+    responsePath: readFlagValue(argv, '--stats-response-path'),
+    openBrowser: hasFlag(argv, '--stats-daemon-open-browser'),
+    daemonScriptPath: path.join(__dirname, 'stats-daemon-runner.js'),
+    userDataPath,
+  };
+}
+
+async function waitForDaemonResponse(responsePath: string): Promise<StatsCliCommandResponse> {
+  const deadline = Date.now() + STATS_DAEMON_RESPONSE_TIMEOUT_MS;
+  while (Date.now() < deadline) {
+    try {
+      if (fs.existsSync(responsePath)) {
+        return JSON.parse(fs.readFileSync(responsePath, 'utf8')) as StatsCliCommandResponse;
+      }
+    } catch {
+      // retry until timeout
+    }
+    await new Promise((resolve) => setTimeout(resolve, 100));
+  }
+
+  return {
+    ok: false,
+    error: 'Timed out waiting for stats daemon startup response.',
+  };
+}
+
+export async function runStatsDaemonControlFromProcess(userDataPath: string): Promise<number> {
+  const args = parseControlArgs(process.argv, userDataPath);
+  const statePath = path.join(userDataPath, 'stats-daemon.json');
+
+  const writeFailureResponse = (message: string): void => {
+    if (args.responsePath) {
+      try {
+        writeStatsCliCommandResponse(args.responsePath, {
+          ok: false,
+          error: message,
+        });
+      } catch {
+        // ignore secondary response-write failures
+      }
+    }
+  };
+
+  const handler = createRunStatsDaemonControlHandler({
+    statePath,
+    readState: () => readBackgroundStatsServerState(statePath),
+    removeState: () => {
+      removeBackgroundStatsServerState(statePath);
+    },
+    isProcessAlive: (pid) => isBackgroundStatsServerProcessAlive(pid),
+    resolveUrl: (state) => resolveBackgroundStatsServerUrl(state),
+    spawnDaemon: async (options) => {
+      const childArgs = [options.scriptPath, '--stats-user-data-path', options.userDataPath];
+      if (options.responsePath) {
+        childArgs.push('--stats-response-path', options.responsePath);
+      }
+      const logLevel = readFlagValue(process.argv, '--log-level');
+      if (logLevel) {
+        childArgs.push('--log-level', logLevel);
+      }
+      const child = spawn(process.execPath, childArgs, {
+        detached: true,
+        stdio: 'ignore',
+        env: {
+          ...sanitizeStartupEnv(process.env),
+          ELECTRON_RUN_AS_NODE: '1',
+        },
+      });
+      child.unref();
+      return child.pid ?? 0;
+    },
+    waitForDaemonResponse,
+    openExternal: async (url) => shell.openExternal(url),
+    writeResponse: writeStatsCliCommandResponse,
+    killProcess: (pid, signal) => {
+      process.kill(pid, signal);
+    },
+    sleep: async (ms) => new Promise((resolve) => setTimeout(resolve, ms)),
+  });
+
+  try {
+    return await handler(args);
+  } catch (error) {
+    const message = error instanceof Error ? error.message : String(error);
+    writeFailureResponse(message);
+    return 1;
+  }
+}

src/stats-daemon-runner.ts

@@ -0,0 +1,225 @@
+import fs from 'node:fs';
+import os from 'node:os';
+import path from 'node:path';
+import { spawn } from 'node:child_process';
+import { ConfigService } from './config/service';
+import { createLogger, setLogLevel } from './logger';
+import { ImmersionTrackerService } from './core/services/immersion-tracker-service';
+import { createCoverArtFetcher } from './core/services/anilist/cover-art-fetcher';
+import { createAnilistRateLimiter } from './core/services/anilist/rate-limiter';
+import { startStatsServer } from './core/services/stats-server';
+import {
+  removeBackgroundStatsServerState,
+  writeBackgroundStatsServerState,
+} from './main/runtime/stats-daemon';
+import { writeStatsCliCommandResponse } from './main/runtime/stats-cli-command';
+import { createInvokeStatsWordHelperHandler, type StatsWordHelperResponse } from './stats-word-helper-client';
+
+const logger = createLogger('stats-daemon');
+const STATS_WORD_HELPER_RESPONSE_TIMEOUT_MS = 20_000;
+
+function readFlagValue(argv: string[], flag: string): string | undefined {
+  for (let i = 0; i < argv.length; i += 1) {
+    const arg = argv[i];
+    if (!arg) continue;
+    if (arg === flag) {
+      const value = argv[i + 1];
+      if (value && !value.startsWith('--')) {
+        return value;
+      }
+      return undefined;
+    }
+    if (arg.startsWith(`${flag}=`)) {
+      return arg.split('=', 2)[1];
+    }
+  }
+  return undefined;
+}
+
+async function waitForWordHelperResponse(responsePath: string): Promise<StatsWordHelperResponse> {
+  const deadline = Date.now() + STATS_WORD_HELPER_RESPONSE_TIMEOUT_MS;
+  while (Date.now() < deadline) {
+    try {
+      if (fs.existsSync(responsePath)) {
+        return JSON.parse(fs.readFileSync(responsePath, 'utf8')) as StatsWordHelperResponse;
+      }
+    } catch {
+      // retry until timeout
+    }
+    await new Promise((resolve) => setTimeout(resolve, 100));
+  }
+
+  return {
+    ok: false,
+    error: 'Timed out waiting for stats word helper response.',
+  };
+}
+
+const invokeStatsWordHelper = createInvokeStatsWordHelperHandler({
+  createTempDir: (prefix) => fs.mkdtempSync(path.join(os.tmpdir(), prefix)),
+  joinPath: (...parts) => path.join(...parts),
+  spawnHelper: async (options) => {
+    const childArgs = [
+      options.scriptPath,
+      '--stats-word-helper-response-path',
+      options.responsePath,
+      '--stats-word-helper-user-data-path',
+      options.userDataPath,
+      '--stats-word-helper-word',
+      options.word,
+    ];
+    const logLevel = readFlagValue(process.argv, '--log-level');
+    if (logLevel) {
+      childArgs.push('--log-level', logLevel);
+    }
+    const child = spawn(process.execPath, childArgs, {
+      stdio: 'ignore',
+      env: {
+        ...process.env,
+        ELECTRON_RUN_AS_NODE: undefined,
+      },
+    });
+    return await new Promise<number>((resolve) => {
+      child.once('exit', (code) => resolve(code ?? 1));
+      child.once('error', () => resolve(1));
+    });
+  },
+  waitForResponse: waitForWordHelperResponse,
+  removeDir: (targetPath) => {
+    fs.rmSync(targetPath, { recursive: true, force: true });
+  },
+});
+
+const userDataPath = readFlagValue(process.argv, '--stats-user-data-path')?.trim();
+const responsePath = readFlagValue(process.argv, '--stats-response-path')?.trim();
+const logLevel = readFlagValue(process.argv, '--log-level');
+
+if (logLevel) {
+  setLogLevel(logLevel, 'cli');
+}
+
+if (!userDataPath) {
+  if (responsePath) {
+    writeStatsCliCommandResponse(responsePath, {
+      ok: false,
+      error: 'Missing --stats-user-data-path for stats daemon runner.',
+    });
+  }
+  process.exit(1);
+}
+
+const daemonUserDataPath = userDataPath;
+
+const statePath = path.join(userDataPath, 'stats-daemon.json');
+const knownWordCachePath = path.join(userDataPath, 'known-words-cache.json');
+const statsDistPath = path.join(__dirname, '..', 'stats', 'dist');
+const wordHelperScriptPath = path.join(__dirname, 'stats-word-helper.js');
+
+let tracker: ImmersionTrackerService | null = null;
+let statsServer: ReturnType<typeof startStatsServer> | null = null;
+
+function writeFailureResponse(message: string): void {
+  if (!responsePath) return;
+  writeStatsCliCommandResponse(responsePath, { ok: false, error: message });
+}
+
+function clearOwnedState(): void {
+  const rawState = (() => {
+    try {
+      return JSON.parse(fs.readFileSync(statePath, 'utf8')) as { pid?: number };
+    } catch {
+      return null;
+    }
+  })();
+  if (rawState?.pid === process.pid) {
+    removeBackgroundStatsServerState(statePath);
+  }
+}
+
+function shutdown(code = 0): void {
+  try {
+    statsServer?.close();
+  } catch {
+    // ignore
+  }
+  statsServer = null;
+  try {
+    tracker?.destroy();
+  } catch {
+    // ignore
+  }
+  tracker = null;
+  clearOwnedState();
+  process.exit(code);
+}
+
+process.on('SIGINT', () => shutdown(0));
+process.on('SIGTERM', () => shutdown(0));
+
+async function main(): Promise<void> {
+  try {
+    const configService = new ConfigService(daemonUserDataPath);
+    const config = configService.getConfig();
+    if (config.immersionTracking?.enabled === false) {
+      throw new Error('Immersion tracking is disabled in config.');
+    }
+
+    const configuredDbPath = config.immersionTracking?.dbPath?.trim() || '';
+    tracker = new ImmersionTrackerService({
+      dbPath: configuredDbPath || path.join(daemonUserDataPath, 'immersion.sqlite'),
+      policy: {
+        batchSize: config.immersionTracking.batchSize,
+        flushIntervalMs: config.immersionTracking.flushIntervalMs,
+        queueCap: config.immersionTracking.queueCap,
+        payloadCapBytes: config.immersionTracking.payloadCapBytes,
+        maintenanceIntervalMs: config.immersionTracking.maintenanceIntervalMs,
+        retention: {
+          eventsDays: config.immersionTracking.retention.eventsDays,
+          telemetryDays: config.immersionTracking.retention.telemetryDays,
+          sessionsDays: config.immersionTracking.retention.sessionsDays,
+          dailyRollupsDays: config.immersionTracking.retention.dailyRollupsDays,
+          monthlyRollupsDays: config.immersionTracking.retention.monthlyRollupsDays,
+          vacuumIntervalDays: config.immersionTracking.retention.vacuumIntervalDays,
+        },
+      },
+    });
+    tracker.setCoverArtFetcher(
+      createCoverArtFetcher(createAnilistRateLimiter(), createLogger('stats-daemon:cover-art')),
+    );
+
+    statsServer = startStatsServer({
+      port: config.stats.serverPort,
+      staticDir: statsDistPath,
+      tracker,
+      knownWordCachePath,
+      ankiConnectConfig: config.ankiConnect,
+      addYomitanNote: async (word: string) =>
+        await invokeStatsWordHelper({
+          helperScriptPath: wordHelperScriptPath,
+          userDataPath: daemonUserDataPath,
+          word,
+        }),
+    });
+
+    writeBackgroundStatsServerState(statePath, {
+      pid: process.pid,
+      port: config.stats.serverPort,
+      startedAtMs: Date.now(),
+    });
+
+    if (responsePath) {
+      writeStatsCliCommandResponse(responsePath, {
+        ok: true,
+        url: `http://127.0.0.1:${config.stats.serverPort}`,
+      });
+    }
+    logger.info(`Background stats daemon listening on http://127.0.0.1:${config.stats.serverPort}`);
+  } catch (error) {
+    const message = error instanceof Error ? error.message : String(error);
+    logger.error('Failed to start stats daemon', message);
+    writeFailureResponse(message);
+    shutdown(1);
+  }
+}
+
+void main();

src/stats-word-helper-client.test.ts

@@ -0,0 +1,57 @@
+import assert from 'node:assert/strict';
+import test from 'node:test';
+import { createInvokeStatsWordHelperHandler } from './stats-word-helper-client';
+
+test('word helper client returns note id when helper responds before exit', async () => {
+  const calls: string[] = [];
+  const handler = createInvokeStatsWordHelperHandler({
+    createTempDir: () => '/tmp/stats-word-helper',
+    joinPath: (...parts) => parts.join('/'),
+    spawnHelper: async (options) => {
+      calls.push(
+        `spawnHelper:${options.scriptPath}:${options.responsePath}:${options.userDataPath}:${options.word}`,
+      );
+      return new Promise<number>((resolve) => setTimeout(() => resolve(0), 20));
+    },
+    waitForResponse: async (responsePath) => {
+      calls.push(`waitForResponse:${responsePath}`);
+      return { ok: true, noteId: 123 };
+    },
+    removeDir: (targetPath) => {
+      calls.push(`removeDir:${targetPath}`);
+    },
+  });
+
+  const noteId = await handler({
+    helperScriptPath: '/tmp/stats-word-helper.js',
+    userDataPath: '/tmp/SubMiner',
+    word: '猫',
+  });
+
+  assert.equal(noteId, 123);
+  assert.deepEqual(calls, [
+    'spawnHelper:/tmp/stats-word-helper.js:/tmp/stats-word-helper/response.json:/tmp/SubMiner:猫',
+    'waitForResponse:/tmp/stats-word-helper/response.json',
+    'removeDir:/tmp/stats-word-helper',
+  ]);
+});
+
+test('word helper client throws helper response errors', async () => {
+  const handler = createInvokeStatsWordHelperHandler({
+    createTempDir: () => '/tmp/stats-word-helper',
+    joinPath: (...parts) => parts.join('/'),
+    spawnHelper: async () => 0,
+    waitForResponse: async () => ({ ok: false, error: 'helper failed' }),
+    removeDir: () => {},
+  });
+
+  await assert.rejects(
+    async () =>
+      handler({
+        helperScriptPath: '/tmp/stats-word-helper.js',
+        userDataPath: '/tmp/SubMiner',
+        word: '猫',
+      }),
+    /helper failed/,
+  );
+});

src/stats-word-helper-client.ts

@@ -0,0 +1,62 @@
+export type StatsWordHelperResponse = {
+  ok: boolean;
+  noteId?: number;
+  error?: string;
+};
+
+export function createInvokeStatsWordHelperHandler(deps: {
+  createTempDir: (prefix: string) => string;
+  joinPath: (...parts: string[]) => string;
+  spawnHelper: (options: {
+    scriptPath: string;
+    responsePath: string;
+    userDataPath: string;
+    word: string;
+  }) => Promise<number>;
+  waitForResponse: (responsePath: string) => Promise<StatsWordHelperResponse>;
+  removeDir: (targetPath: string) => void;
+}) {
+  return async (options: {
+    helperScriptPath: string;
+    userDataPath: string;
+    word: string;
+  }): Promise<number> => {
+    const tempDir = deps.createTempDir('subminer-stats-word-helper-');
+    const responsePath = deps.joinPath(tempDir, 'response.json');
+
+    try {
+      const helperExitPromise = deps.spawnHelper({
+        scriptPath: options.helperScriptPath,
+        responsePath,
+        userDataPath: options.userDataPath,
+        word: options.word,
+      });
+
+      const startupResult = await Promise.race([
+        deps.waitForResponse(responsePath).then((response) => ({ kind: 'response' as const, response })),
+        helperExitPromise.then((status) => ({ kind: 'exit' as const, status })),
+      ]);
+
+      let response: StatsWordHelperResponse;
+      if (startupResult.kind === 'response') {
+        response = startupResult.response;
+      } else {
+        if (startupResult.status !== 0) {
+          throw new Error(`Stats word helper exited before response (status ${startupResult.status}).`);
+        }
+        response = await deps.waitForResponse(responsePath);
+      }
+
+      const exitStatus = await helperExitPromise;
+      if (exitStatus !== 0) {
+        throw new Error(`Stats word helper exited with status ${exitStatus}.`);
+      }
+      if (!response.ok || typeof response.noteId !== 'number') {
+        throw new Error(response.error || 'Stats word helper failed.');
+      }
+      return response.noteId;
+    } finally {
+      deps.removeDir(tempDir);
+    }
+  };
+}

src/stats-word-helper.ts

@@ -0,0 +1,193 @@
+import fs from 'node:fs';
+import path from 'node:path';
+import { app, protocol } from 'electron';
+import type { BrowserWindow, Extension, Session } from 'electron';
+import { ConfigService } from './config/service';
+import { createLogger, setLogLevel } from './logger';
+import { loadYomitanExtension } from './core/services/yomitan-extension-loader';
+import {
+  addYomitanNoteViaSearch,
+  syncYomitanDefaultAnkiServer,
+} from './core/services/tokenizer/yomitan-parser-runtime';
+import type { StatsWordHelperResponse } from './stats-word-helper-client';
+import { clearYomitanExtensionRuntimeState } from './core/services/yomitan-extension-runtime-state';
+
+protocol.registerSchemesAsPrivileged([
+  {
+    scheme: 'chrome-extension',
+    privileges: {
+      standard: true,
+      secure: true,
+      supportFetchAPI: true,
+      corsEnabled: true,
+      bypassCSP: true,
+    },
+  },
+]);
+
+const logger = createLogger('stats-word-helper');
+
+function readFlagValue(argv: string[], flag: string): string | undefined {
+  for (let i = 0; i < argv.length; i += 1) {
+    const arg = argv[i];
+    if (!arg) continue;
+    if (arg === flag) {
+      const value = argv[i + 1];
+      if (value && !value.startsWith('--')) {
+        return value;
+      }
+      return undefined;
+    }
+    if (arg.startsWith(`${flag}=`)) {
+      return arg.split('=', 2)[1];
+    }
+  }
+  return undefined;
+}
+
+function writeResponse(responsePath: string | undefined, payload: StatsWordHelperResponse): void {
+  if (!responsePath) return;
+  fs.mkdirSync(path.dirname(responsePath), { recursive: true });
+  fs.writeFileSync(responsePath, JSON.stringify(payload, null, 2), 'utf8');
+}
+
+const responsePath = readFlagValue(process.argv, '--stats-word-helper-response-path')?.trim();
+const userDataPath = readFlagValue(process.argv, '--stats-word-helper-user-data-path')?.trim();
+const word = readFlagValue(process.argv, '--stats-word-helper-word');
+const logLevel = readFlagValue(process.argv, '--log-level');
+
+if (logLevel) {
+  setLogLevel(logLevel, 'cli');
+}
+
+if (!userDataPath || !word) {
+  writeResponse(responsePath, {
+    ok: false,
+    error: 'Missing stats word helper arguments.',
+  });
+  app.exit(1);
+}
+
+app.setName('SubMiner');
+app.setPath('userData', userDataPath!);
+
+let yomitanExt: Extension | null = null;
+let yomitanSession: Session | null = null;
+let yomitanParserWindow: BrowserWindow | null = null;
+let yomitanParserReadyPromise: Promise<void> | null = null;
+let yomitanParserInitPromise: Promise<boolean> | null = null;
+
+function cleanup(): void {
+  clearYomitanExtensionRuntimeState({
+    getYomitanParserWindow: () => yomitanParserWindow,
+    setYomitanParserWindow: () => {
+      yomitanParserWindow = null;
+    },
+    setYomitanParserReadyPromise: () => {
+      yomitanParserReadyPromise = null;
+    },
+    setYomitanParserInitPromise: () => {
+      yomitanParserInitPromise = null;
+    },
+    setYomitanExtension: () => {
+      yomitanExt = null;
+    },
+    setYomitanSession: () => {
+      yomitanSession = null;
+    },
+  });
+}
+
+async function main(): Promise<void> {
+  try {
+    const configService = new ConfigService(userDataPath!);
+    const config = configService.getConfig();
+    const extension = await loadYomitanExtension({
+      userDataPath: userDataPath!,
+      getYomitanParserWindow: () => yomitanParserWindow,
+      setYomitanParserWindow: (window) => {
+        yomitanParserWindow = window;
+      },
+      setYomitanParserReadyPromise: (promise) => {
+        yomitanParserReadyPromise = promise;
+      },
+      setYomitanParserInitPromise: (promise) => {
+        yomitanParserInitPromise = promise;
+      },
+      setYomitanExtension: (extensionValue) => {
+        yomitanExt = extensionValue;
+      },
+      setYomitanSession: (sessionValue) => {
+        yomitanSession = sessionValue;
+      },
+    });
+    if (!extension) {
+      throw new Error('Yomitan extension failed to load.');
+    }
+
+    await syncYomitanDefaultAnkiServer(
+      config.ankiConnect?.url || 'http://127.0.0.1:8765',
+      {
+        getYomitanExt: () => yomitanExt,
+        getYomitanSession: () => yomitanSession,
+        getYomitanParserWindow: () => yomitanParserWindow,
+        setYomitanParserWindow: (window) => {
+          yomitanParserWindow = window;
+        },
+        getYomitanParserReadyPromise: () => yomitanParserReadyPromise,
+        setYomitanParserReadyPromise: (promise) => {
+          yomitanParserReadyPromise = promise;
+        },
+        getYomitanParserInitPromise: () => yomitanParserInitPromise,
+        setYomitanParserInitPromise: (promise) => {
+          yomitanParserInitPromise = promise;
+        },
+      },
+      logger,
+      { forceOverride: true },
+    );
+
+    const noteId = await addYomitanNoteViaSearch(
+      word!,
+      {
+        getYomitanExt: () => yomitanExt,
+        getYomitanSession: () => yomitanSession,
+        getYomitanParserWindow: () => yomitanParserWindow,
+        setYomitanParserWindow: (window) => {
+          yomitanParserWindow = window;
+        },
+        getYomitanParserReadyPromise: () => yomitanParserReadyPromise,
+        setYomitanParserReadyPromise: (promise) => {
+          yomitanParserReadyPromise = promise;
+        },
+        getYomitanParserInitPromise: () => yomitanParserInitPromise,
+        setYomitanParserInitPromise: (promise) => {
+          yomitanParserInitPromise = promise;
+        },
+      },
+      logger,
+    );
+
+    if (typeof noteId !== 'number') {
+      throw new Error('Yomitan failed to create note.');
+    }
+
+    writeResponse(responsePath, {
+      ok: true,
+      noteId,
+    });
+    cleanup();
+    app.exit(0);
+  } catch (error) {
+    const message = error instanceof Error ? error.message : String(error);
+    logger.error('Stats word helper failed', message);
+    writeResponse(responsePath, {
+      ok: false,
+      error: message,
+    });
+    cleanup();
+    app.exit(1);
+  }
+}
+
+void app.whenReady().then(() => main());