fix(anime): thread episode metadata through stream playback and fix seas

- Split anime browser stream titles into series/season/episode fields (episode-metadata.ts) instead of one joined string, so stats grouping, the mpv title, and the Jimaku/TsukiHime modals all get real values instead of a filename-derived "m3u8"
- Fix AniList season resolver to walk through split-cour sequels and specials without counting them as a season, and to surface rate-limit/network failures instead of falling through to a wrong air-order guess
- Add a Season field to the TsukiHime modal and include later seasons in its search query
- Rewrite WebVTT subtitle tracks as SRT before handing them to alass, since alass has no VTT support and streams serve VTT
- Update CHANGELOG and troubleshooting docs

src/main/runtime/stream-playback-metadata.test.ts

@@ -0,0 +1,77 @@
+import test from 'node:test';
+import assert from 'node:assert/strict';
+import {
+  createStreamPlaybackMetadataStore,
+  toAnilistMediaGuess,
+  toJimakuMediaInfo,
+} from './stream-playback-metadata';
+import type { AnimeStreamMetadata } from '../../anime-bridge/episode-metadata';
+
+function metadata(overrides: Partial<AnimeStreamMetadata> = {}): AnimeStreamMetadata {
+  return {
+    mediaPath: 'http://127.0.0.1:41234/video/abc.m3u8',
+    statsPath: 'animebrowser://9001/%2Fanime%2Fmushoku/%2Fwatch%2Fep-4',
+    seriesTitle: 'Mushoku Tensei: Jobless Reincarnation',
+    seasonNumber: 3,
+    episodeNumber: 4,
+    episodeTitle: null,
+    displayTitle: 'Mushoku Tensei: Jobless Reincarnation S03E04',
+    ...overrides,
+  };
+}
+
+test('the store answers for the stream URL and for the stats path', () => {
+  const store = createStreamPlaybackMetadataStore();
+  const current = metadata();
+  store.set(current);
+
+  assert.equal(store.match(current.mediaPath), current);
+  assert.equal(store.match(current.statsPath), current);
+  assert.equal(store.match(`  ${current.mediaPath}  `), current);
+});
+
+test('the store stops answering once the player moves on', () => {
+  const store = createStreamPlaybackMetadataStore();
+  store.set(metadata());
+
+  assert.equal(store.match('/home/user/Videos/local.mkv'), null);
+  assert.equal(store.match(null), null);
+  assert.equal(store.match(''), null);
+
+  store.clear();
+  assert.equal(store.match(metadata().mediaPath), null);
+});
+
+test('toJimakuMediaInfo prefills the modals with the source-reported fields', () => {
+  assert.deepEqual(toJimakuMediaInfo(metadata()), {
+    title: 'Mushoku Tensei: Jobless Reincarnation',
+    season: 3,
+    episode: 4,
+    confidence: 'high',
+    filename: 'Mushoku Tensei: Jobless Reincarnation S03E04',
+    rawTitle: 'Mushoku Tensei: Jobless Reincarnation S03E04',
+  });
+});
+
+test('toJimakuMediaInfo drops to low confidence when there is no episode', () => {
+  const info = toJimakuMediaInfo(metadata({ episodeNumber: null, seasonNumber: null }));
+  assert.equal(info.episode, null);
+  assert.equal(info.confidence, 'low');
+  assert.equal(info.title, 'Mushoku Tensei: Jobless Reincarnation');
+});
+
+test('toAnilistMediaGuess reports the stream fields verbatim', () => {
+  assert.deepEqual(toAnilistMediaGuess(metadata()), {
+    title: 'Mushoku Tensei: Jobless Reincarnation',
+    season: 3,
+    episode: 4,
+    source: 'stream',
+  });
+});
+
+test('toAnilistMediaGuess declines a special so the caller can fall back', () => {
+  // AniList progress counts whole episodes; a 6.5 special is not one of them.
+  assert.equal(toAnilistMediaGuess(metadata({ episodeNumber: 6.5 })), null);
+  assert.equal(toAnilistMediaGuess(metadata({ episodeNumber: null })), null);
+  assert.equal(toAnilistMediaGuess(metadata({ seriesTitle: '' })), null);
+});