feat(subtitles): add regex subtitle filters with built-in presets (#318)

- Add `subtitleFilter` config with four presets: parentheses, brackets, speaker prefix and music symbols. Custom regex rules run after the presets.
- Filter primary text where it enters the app (live `sub-text` and parsed cues), so the overlay, sidebar, mining and stats all get the same filtered text.
- Changes hot-reload: the current line is read again and the active track is parsed again, using the filter config as the prefetch parse key.
- Add a custom rule editor in Settings under Behavior → Subtitle Filters that checks patterns as you type.
- Update the config example, the configuration docs and the architecture domains doc, and add a changelog fragment.

src/main/runtime/config-hot-reload-handlers.ts

@@ -20,6 +20,8 @@ type ConfigHotReloadAppliedDeps = {
   invalidateTokenizationCache?: () => void;
   refreshSubtitlePrefetch?: () => void;
   refreshCurrentSubtitle?: () => void;
+  /** Re-reads the live line and re-parses the active cue list through the new filters. */
+  refreshSubtitleFilter?: () => void;
   setLogLevel?: (level: ResolvedConfig['logging']['level']) => void;
   setLogRotation?: (rotation: ResolvedConfig['logging']['rotation']) => void;
   setLogFileToggles?: (files: ResolvedConfig['logging']['files']) => void;
@@ -180,6 +182,10 @@ export function createConfigHotReloadAppliedHandler(deps: ConfigHotReloadApplied
       deps.applyAnkiRuntimeConfigPatch(ankiPatch);
     }
 
+    if (diff.hotReloadFields.includes('subtitleFilter')) {
+      deps.refreshSubtitleFilter?.();
+    }
+
     if (hasAnnotationRuntimeHotReload(diff)) {
       deps.invalidateTokenizationCache?.();
       deps.refreshSubtitlePrefetch?.();

src/main/runtime/subtitle-prefetch-init.test.ts

@@ -252,7 +252,7 @@ test('subtitle prefetch init logs a warning when the source parses to zero cues'
   assert.match(warnings[0]!, /\[subtitle-prefetch\].*0 cues.*\/tmp\/broken\.ass/);
 });
 
-function createTrackingController(loadContent: () => string) {
+function createTrackingController(loadContent: () => string, getParseKey?: () => string) {
   let currentService: SubtitlePrefetchService | null = null;
   const events: string[] = [];
   const cueUpdates: Array<string | null> = [];
@@ -265,6 +265,7 @@ function createTrackingController(loadContent: () => string) {
     },
     loadSubtitleSourceText: async () => loadContent(),
     parseSubtitleCues: (content): SubtitleCue[] => [{ startTime: 0, endTime: 1, text: content }],
+    getParseKey,
     createSubtitlePrefetchService: () => {
       const id = ++serviceCount;
       return {
@@ -308,6 +309,20 @@ test('re-initializing a source whose content changed restarts the service', asyn
   assert.deepEqual(events, ['start:1', 'stop:1', 'start:2']);
 });
 
+test('re-initializing an unchanged source re-parses when the parse key changed', async () => {
+  let parseKey = 'filters-off';
+  const { controller, events } = createTrackingController(
+    () => 'content',
+    () => parseKey,
+  );
+
+  await controller.initSubtitlePrefetch('track-1.srt', 0);
+  parseKey = 'filters-on';
+  await controller.initSubtitlePrefetch('track-1.srt', 0);
+
+  assert.deepEqual(events, ['start:1', 'stop:1', 'start:2']);
+});
+
 test('subtitle prefetch init warms overlap lines without publishing them as cues', async () => {
   let prefetchedTexts: string[] = [];
   let publishedTexts: string[] = [];

src/main/runtime/subtitle-prefetch-init.ts

@@ -11,6 +11,8 @@ export interface SubtitlePrefetchInitControllerDeps {
   setCurrentService: (service: SubtitlePrefetchService | null) => void;
   loadSubtitleSourceText: (source: string) => Promise<string>;
   parseSubtitleCues: (content: string, filename: string) => SubtitleCue[];
+  /** Changes whenever parseSubtitleCues would produce different cues for the same content. */
+  getParseKey?: () => string;
   createSubtitlePrefetchService: (deps: SubtitlePrefetchServiceDeps) => SubtitlePrefetchService;
   tokenizeSubtitle: (text: string) => Promise<SubtitleData | null>;
   preCacheTokenization: (text: string, data: SubtitleData) => void;
@@ -37,7 +39,12 @@ export function createSubtitlePrefetchInitController(
   // What the running service was built from. Startup fires several inits for one source
   // (Jellyfin preload seed, sid change, each track-list update); restarting on each would
   // discard the in-flight tokenization and re-queue the priority window behind it.
-  let activeSource: { key: string; content: string; cues: SubtitleCue[] } | null = null;
+  let activeSource: {
+    key: string;
+    content: string;
+    parseKey: string;
+    cues: SubtitleCue[];
+  } | null = null;
 
   const stopCurrentService = (): void => {
     deps.getCurrentService()?.stop();
@@ -67,9 +74,11 @@ export function createSubtitlePrefetchInitController(
       if (revision !== initRevision) {
         return;
       }
+      const parseKey = deps.getParseKey?.() ?? '';
       if (
         activeSource?.key === sourceKey &&
         activeSource.content === content &&
+        activeSource.parseKey === parseKey &&
         deps.getCurrentService()
       ) {
         // A track change clears the published cues synchronously, so republish them.
@@ -106,7 +115,7 @@ export function createSubtitlePrefetchInitController(
       }
 
       deps.setCurrentService(nextService);
-      activeSource = { key: sourceKey, content, cues };
+      activeSource = { key: sourceKey, content, parseKey, cues };
       deps.onParsedSubtitleCuesChanged?.(cues, sourceKey);
       nextService.start(currentTimePos);
       deps.logInfo(