Numbered items: also after a disc code (karaoke)

"Spotlight - 83xx's [16/19] - \"SC8367-12 - Wynette, Tammy - Singing My
Song.zip\"": the disc-and-track code isn't a bare track number, so the
poster-tag rule keyed every track by its own name. A stem starting with
an upper-case code and digits before the track number (SC8367-12,
ZMP050-04) is a numbered item too. Both implementations; tests; fixtures
identical.

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

lib/release/identity.ts

@@ -237,7 +237,8 @@ export function releaseIdentity(input: ReleaseInput): ReleaseIdentity | null {
   // subject names as a set or album ("IMG_3086.jpg", "072 - Die Teufelsuhr.MP3"), nor for numbered items of
   // a set ("ai-engineer-complete [401/465] - "003 Defining Tools with JSON Schema.mp4"": a course's 465
   // lessons were releases of their own; LOG.md 2026-10-11 (7)). Uploads hours apart are apart anyway.
-  const numbered = /^\d{1,3}[ ._-]/.test(stem)
+  // Also after a disc code ("SC8367-12 - Wynette, Tammy - Singing My Song", karaoke discs).
+  const numbered = /^(?:[A-Z]{1,5}\d{2,6}[-_ ])?\d{1,3}[ ._-]/.test(stem)
   const tag = !image && !numbered && !AUDIO.test(input.name) && describes(stem) && !looksRandom(stem) && isPosterTag(remainder, stem)
   // An image set without a counter: the image's name up to its last number, without numbers
   // ("Kitchen Hottie 1 set233-76-lg" → "Kitchen Hottie set", "bm_jessica_blb_h087" → "bm jessica blb h").