fix(subtitles): release prefetch pause across all priming paths

The repeated-subtitle pause leak was only fixed for ordinary subtitle
changes. Startup autoplay priming and visible-overlay priming pause the same
way and also ignored whether any tokenization was scheduled, so a cache miss
on text the controller already holds (mining a card while the line is on
screen) left prefetching idle for the rest of the cue.

Pause and release are now one operation via pausePrefetchUntilEmit, and both
controller entry points report whether an emit is expected. A repeat arriving
while a run is already in flight keeps the pause, since that run still emits.

Also invalidate the character dictionary lookups centrally from the sync
completion handler instead of at three manager call sites. Ordinary selection
sync never invalidated them, so a stale non-null name candidate list could
skip a newly added name for up to five seconds; a missing list falls back to
the exhaustive scan, but a stale one does not. Ordering matters: the
invalidation runs before the subtitle refreshes so they re-tokenize against
the new dictionary content.

Docs: subtitle-overlay-priming no longer claims every subtitle change calls
onSeek().

src/main/runtime/autoplay-subtitle-priming-runtime.test.ts

@@ -42,8 +42,8 @@ test('scheduleSubtitlePrefetchRefresh logs refresh failures from timer callback'
     setActiveParsedSubtitleMediaPath: () => {},
     subtitleProcessingController: {
       consumeCachedSubtitle: () => null,
-      onSubtitleChange: () => {},
-      refreshCurrentSubtitle: () => {},
+      onSubtitleChange: () => true,
+      refreshCurrentSubtitle: () => true,
     },
     emitSubtitlePayload: () => {},
     getSubtitlePrefetchService: () => null,
@@ -93,13 +93,24 @@ test('primeCurrentSubtitleForAutoplay refreshes active subtitle cues when mpv su
     setActiveParsedSubtitleMediaPath: () => {},
     subtitleProcessingController: {
       consumeCachedSubtitle: () => null,
-      onSubtitleChange: (text) => calls.push(`change:${text}`),
-      refreshCurrentSubtitle: (text) => calls.push(`refresh:${text ?? ''}`),
+      onSubtitleChange: (text) => {
+        calls.push(`change:${text}`);
+        return true;
+      },
+      refreshCurrentSubtitle: (text) => {
+        calls.push(`refresh:${text ?? ''}`);
+        return true;
+      },
     },
     emitSubtitlePayload: (payload, options) =>
       calls.push(`emit:${payload.text}:resume=${options?.resumePrefetch !== false}`),
     getSubtitlePrefetchService: () => ({
-      pause: () => calls.push('prefetch:pause'),
+      pause: () => {
+        calls.push('prefetch:pause');
+      },
+      resume: () => {
+        calls.push('prefetch:resume');
+      },
     }),
     getLastObservedTimePos: () => 12,
     getVisibleOverlayVisible: () => true,
@@ -151,13 +162,24 @@ test('primeCurrentSubtitleForAutoplay emits raw first paint on cache miss before
     setActiveParsedSubtitleMediaPath: () => {},
     subtitleProcessingController: {
       consumeCachedSubtitle: () => null,
-      onSubtitleChange: (text) => calls.push(`change:${text}`),
-      refreshCurrentSubtitle: (text) => calls.push(`refresh:${text ?? ''}`),
+      onSubtitleChange: (text) => {
+        calls.push(`change:${text}`);
+        return true;
+      },
+      refreshCurrentSubtitle: (text) => {
+        calls.push(`refresh:${text ?? ''}`);
+        return true;
+      },
     },
     emitSubtitlePayload: (payload, options) =>
       calls.push(`emit:${payload.text}:resume=${options?.resumePrefetch !== false}`),
     getSubtitlePrefetchService: () => ({
-      pause: () => calls.push('prefetch:pause'),
+      pause: () => {
+        calls.push('prefetch:pause');
+      },
+      resume: () => {
+        calls.push('prefetch:resume');
+      },
     }),
     getLastObservedTimePos: () => 12,
     getVisibleOverlayVisible: () => true,
@@ -179,3 +201,65 @@ test('primeCurrentSubtitleForAutoplay emits raw first paint on cache miss before
     'change:起動字幕',
   ]);
 });
+
+test('primeCurrentSubtitleForAutoplay releases the prefetch pause when no tokenization is scheduled', async () => {
+  const calls: string[] = [];
+  let currentSubText = '';
+  const mediaPath = '/media/video.mkv';
+
+  const runtime = createAutoplaySubtitlePrimingRuntime({
+    getCurrentMediaPath: () => mediaPath,
+    getMpvClient: () => ({
+      connected: true,
+      currentVideoPath: mediaPath,
+      requestProperty: async (name) => {
+        if (name === 'sub-text') return '起動字幕';
+        return null;
+      },
+    }),
+    setCurrentSubText: (text) => {
+      currentSubText = text;
+    },
+    getCurrentSubText: () => currentSubText,
+    getCurrentSubtitleData: () => null,
+    getActiveParsedSubtitleCues: () => [],
+    setActiveParsedSubtitleMediaPath: () => {},
+    subtitleProcessingController: {
+      // The tokenization cache was invalidated (for example by mining a card),
+      // so the cached payload is gone...
+      consumeCachedSubtitle: () => null,
+      // ...but the controller still holds this text, so it schedules nothing
+      // and no emit will arrive to release the pause.
+      onSubtitleChange: (text) => {
+        calls.push(`change:${text}`);
+        return false;
+      },
+      refreshCurrentSubtitle: () => true,
+    },
+    emitSubtitlePayload: (payload, options) =>
+      calls.push(`emit:${payload.text}:resume=${options?.resumePrefetch !== false}`),
+    getSubtitlePrefetchService: () => ({
+      pause: () => {
+        calls.push('prefetch:pause');
+      },
+      resume: () => {
+        calls.push('prefetch:resume');
+      },
+    }),
+    getLastObservedTimePos: () => 12,
+    getVisibleOverlayVisible: () => true,
+    emitSecondarySubtitle: () => {},
+    initSubtitlePrefetch: async () => {},
+    refreshSubtitlePrefetchFromActiveTrack: async () => {},
+    logDebug: () => {},
+  });
+
+  await runtime.primeCurrentSubtitleForAutoplay(mediaPath);
+
+  assert.deepEqual(calls, [
+    'prefetch:pause',
+    'emit:起動字幕:resume=false',
+    'change:起動字幕',
+    'prefetch:resume',
+  ]);
+});