refactor(main): move plugins, session actions and subtitle generation into assemblies (#327)

* refactor(main): build overlay geometry and pointer interaction in the overlay assembly

Inject Electron's screen (and the stats-window promotion) into the overlay geometry and
visible-overlay interaction runtimes so they load under bun test, then construct both in
createOverlayAssembly together with the overlay visibility composer and the mpv subtitle
suppression handlers. Replace the three regex tests that pinned the moved Linux input and
shape code with behaviour tests on the runtimes.

* refactor(main): move the autoplay-ready gate into the playback assembly

The autoplay-ready gate, its post-warm subtitle prime, the current-media tokenization gate and
managed local subtitle selection all read playback state, and playback signals through the
gate, so createPlaybackAssembly now builds them. The overlay reaches the gate through a getter.

Replace the last four regex guards with behaviour tests: the gate holds the release until the
visible overlay has measured the line and ignores untokenized lines during warmup (playback),
cached autoplay priming never paints raw first and the sidebar media path is tagged only after
prefetch loads (priming runtime), and dashboard mining overrides the Hachidori Anki server only
when the proxy is on (stats server runtime). main-wiring.test.ts is now empty and removed.

* refactor(main): move the plugin host, panel and windows into a plugins assembly

* refactor(main): move session action dispatch and renderer mpv commands into an assembly

createSessionActionsAssembly owns the session action dispatcher, the secondary-subtitle mode cycle, queueing the clipboard's video, and the mpv commands the overlay renderer sends. The runtime option cycle both paths used is now one function.

* refactor(main): move Whisper subtitle generation into an assembly

* refactor(main): resolve subtitle annotation options in a runtime module

The runtime-option-over-config resolution that the texthooker page and the MeCab startup decision share moves out of main.ts into createAnnotationOptions.

* test(main): cover a non-boolean runtime annotation option value

* docs: describe the plugins, session actions and subtitle generation assemblies

Update ownership for overlay geometry and pointer interaction, the autoplay-ready gate, and annotation options; point the overlay priming entry points at their new modules; the main-wiring regex debt is gone.

* build: export MpvClientEvents so declaration emit can name the plugins assembly's return type

docs/architecture/subtitle-overlay-priming.md

@@ -3,7 +3,7 @@
 # Subtitle Overlay Priming
 
 Status: active
-Last verified: 2026-08-19
+Last verified: 2026-11-01
 Owner: Kyle Yasuda
 Read when: debugging subtitle state or blank Linux/X11 overlay windows when the visible overlay is shown or recreated
 
@@ -19,13 +19,14 @@ subtitles do not draw.
 
 ## Entry Points
 
-- `src/main.ts` calls `primeCurrentSubtitleForVisibleOverlay()` when manual visible-overlay show
-  paths run.
-- `src/main.ts` calls `restoreVisibleOverlayWindowShapeForShow()` before visible-overlay show
-  actions on Linux, and `resetVisibleOverlayInputState()` restores a full shape instead of applying
-  an empty shape.
-- `src/main.ts` also restores the Linux/X11 shape after applying mpv overlay bounds, so a newly
-  created 800x600 hidden Electron window cannot keep clipping after it is resized to mpv geometry.
+- The overlay assembly (`src/main/assemblies/overlay.ts`) calls
+  `primeCurrentSubtitleForVisibleOverlay()` when manual visible-overlay show paths run.
+- It calls `restoreVisibleOverlayWindowShapeForShow()` before visible-overlay show actions on
+  Linux, and `resetVisibleOverlayInputState()` restores a full shape instead of applying an empty
+  shape (both in `src/main/runtime/visible-overlay-interaction-runtime.ts`).
+- `src/main/runtime/overlay-geometry-runtime.ts` also restores the Linux/X11 shape after applying
+  mpv overlay bounds, so a newly created 800x600 hidden Electron window cannot keep clipping after
+  it is resized to mpv geometry.
 - `primeCurrentSubtitleForVisibleOverlay()` delegates to
   `primeVisibleOverlaySubtitleFromMpv()` in `src/main/runtime/current-subtitle-snapshot.ts`.
 - `restoreVisibleOverlayWindowShapeForShow()` delegates to `restoreLinuxOverlayWindowShape()` in
@@ -54,7 +55,7 @@ Both `onSubtitleChange` and `refreshCurrentSubtitle` pause `subtitlePrefetchServ
 the matching `subtitleProcessingController` method, giving the visible overlay priority over
 background prefetch work. Prefetch is not re-centered here: restarting the run per line
 (`onSeek`) discarded the in-flight tokenization every time the subtitle changed, so only real
-seeks restart it (see `onTimePosUpdate` in `src/main.ts`).
+seeks restart it (see the time-pos handling in `src/main/assemblies/playback.ts`).
 
 On an uncached autoplay prime the raw payload is emitted here and reported to the controller with
 `notePlainSubtitleEmitted`, so the controller skips its own plain emit for that line and the