fix(anime): scope preferences, paginate sources, harden installs

- Preference store keys entries by extension package + bridge source id; legacy unscoped entries are discarded once instead of being handed to whichever extension asks first
- Source picker's "Load more" appends the next page without duplicating streamed results
- Repository index fetches and subtitle/APK downloads now time out and are size-bounded instead of hanging or growing unbounded
- APK installs are staged to a temp file and renamed into place
- Stream metadata lookup matches the requested path, not only the currently playing one
- Reworked animeui into browse-state/detail-panel/panels.css modules
- Reverted premature CHANGELOG unreleased entries; refreshed anime-browser docs

src/core/services/overlay-window.ts

@@ -93,7 +93,8 @@ export function scheduleOverlayContentReadyFallback(deps: {
   delayMs?: number;
 }): void {
   const setTimeoutFn =
-    deps.setTimeoutFn ?? ((callback: () => void, delayMs: number): unknown => setTimeout(callback, delayMs));
+    deps.setTimeoutFn ??
+    ((callback: () => void, delayMs: number): unknown => setTimeout(callback, delayMs));
   setTimeoutFn(() => {
     if (deps.isContentReady() || deps.isDestroyed()) {
       return;

src/core/services/subsync-extract.test.ts

@@ -163,6 +163,34 @@ test('extractSubtitleTrackToFile rejects a missing local external track', async
   );
 });
 
+test('internal WebVTT extraction uses ffmpeg webvtt muxer with a vtt output file', async () => {
+  const dir = fs.mkdtempSync(path.join(os.tmpdir(), 'subminer-extract-'));
+  const ffmpegPath = path.join(dir, 'ffmpeg-stub');
+  const argsPath = path.join(dir, 'args.txt');
+  fs.writeFileSync(
+    ffmpegPath,
+    `#!/bin/sh\nprintf '%s\\n' "$@" > '${argsPath}'\nfor arg in "$@"; do output="$arg"; done\n: > "$output"\n`,
+    { mode: 0o755 },
+  );
+
+  try {
+    const result = await extractSubtitleTrackToFile({
+      resolveFfmpegPath: () => ffmpegPath,
+      videoPath: path.join(dir, 'video.mkv'),
+      track: { id: 2, type: 'sub', codec: 'webvtt', 'ff-index': 3 },
+      httpHeaders: null,
+    });
+    const args = fs.readFileSync(argsPath, 'utf8').trimEnd().split('\n');
+    const formatIndex = args.indexOf('-f');
+
+    assert.equal(args[formatIndex + 1], 'webvtt');
+    assert.equal(path.extname(result.path), '.vtt');
+    cleanupTemporaryFile(result);
+  } finally {
+    fs.rmSync(dir, { recursive: true, force: true });
+  }
+});
+
 test('cleanupTemporaryFile preserves the retimed output sharing the temp directory', () => {
   const dir = fs.mkdtempSync(path.join(os.tmpdir(), 'subminer-extract-'));
   const sourcePath = path.join(dir, 'remote_track.srt');

src/core/services/subsync-extract.ts

@@ -100,6 +100,7 @@ async function extractInternalTrack(input: SubtitleExtractionInput): Promise<Fil
   if (!extension) {
     throw new Error(`Unsupported subtitle codec: ${input.track.codec ?? 'unknown'}`);
   }
+  const ffmpegMuxer = extension === 'vtt' ? 'webvtt' : extension;
 
   const tempDir = fs.mkdtempSync(path.join(os.tmpdir(), 'subminer-subsync-'));
   try {
@@ -123,7 +124,7 @@ async function extractInternalTrack(input: SubtitleExtractionInput): Promise<Fil
       '-map',
       `0:${ffIndex}`,
       '-f',
-      extension,
+      ffmpegMuxer,
       outputPath,
     ]);