Official release dates from MangaUpdates; peers lower ecosystem dates (BL-0048, BL-0049)

- scraper/metadata/release-dates.js fills x-dates.release from MangaUpdates
  publisher releases. MangaUpdates also lists English back-catalog re-releases,
  so a date is kept only inside the AniList original run, when no scanlation or
  source upload is more than 4 days earlier, and when it fits the release order
  (no lower chapter dated after a higher one). Seasons that restart chapter
  numbers are skipped; dates this job wrote and no longer accepts are withdrawn.
- The scraper refreshes ongoing series nightly before its update checks, only
  while no download runs, and bumps the publish revision so the reader reconciles.
- tools/release-dates.js for a whole library (dry run default). Production dry
  run: 728 chapters dated (Kagurabachi, JJK, Chainsaw Man, One Piece from 928).
- Peer sync: chapters this library already has adopt a peer's earlier ecosystem
  date (job result ecosystemLowered); the peer listing now carries dates.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

peering/test/peering.test.js

@@ -142,9 +142,15 @@ test('mTLS pairing, opt-in catalog, peer queue publication, and revocation', { t
     'The chapter keeps the date it first entered Manga Circus on A, not its arrival on B');
   assert.equal(received['x-dates'].source.at, '2026-09-30T15:00:00.000Z');
   assert.notEqual(received.added, '2026-10-01T08:00:00.000Z', '"added" is the arrival in B\'s own library');
+  // B claims it got the chapter later on its own: the next sync lowers it to A's date again.
+  await fsp.writeFile(path.join(receivedDir, 'chapter.json'), JSON.stringify({ ...received,
+    'x-dates': { ...received['x-dates'], ecosystem: { at: '2026-10-20T00:00:00.000Z', via: 'this server' } } }));
   const second = await run(info, { scope: { mode: 'missing' }, existingPolicy: 'skip-any' },
     { libraryRoot: libB, settings: { chapterMinMs: 500 }, shouldStop: () => false });
   assert.equal(second.publishedCount, 0);
+  assert.equal(second.ecosystemLowered, 1, 'An existing chapter adopts the peer\'s earlier ecosystem date');
+  assert.deepEqual(JSON.parse(await fsp.readFile(path.join(receivedDir, 'chapter.json'), 'utf8'))['x-dates'].ecosystem,
+    { at: '2026-10-01T08:00:00.000Z', via: 'peer ServerA' });
 
   // Simulate B adding one chapter to its imported edition, then sharing it back.
   // A must identify its original folder by the carried origin identity and fetch