Numbered items of a set don't take the poster-tag rule

"ai-engineer-complete [401/465] - \"003 Defining Tools with JSON
Schema.mp4\"": the subject's text shares no word with the lesson's
descriptive name, so it was taken for a poster's constant tag and each of
the course's 465 files keyed a release of its own (releases 75941915,
75941916). A stem starting with a 1-3 digit index and a separator is an
item of a set the subject names, as audio tracks and images already
were; uploads hours apart stay apart by the re-upload rule. Both
implementations; tests; fixtures identical.

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

tests/unit/release/identity.spec.ts

@@ -175,6 +175,14 @@ test.group('release / par2 names', () => {
     assert.equal(par2ReleaseName(['Album.Name-2024-GRP.part01.rar', 'Album.Name-2024-GRP.part02.rar']), 'Album.Name-2024-GRP')
     assert.equal(par2ReleaseName(['only.one.file.2024.mkv']), 'only.one.file.2024')
   })
+  test('numbered items of a set stay one release under the set name (a course, not a poster tag)', ({ assert }) => {
+    const id = (subject: string, name: string) => releaseIdentity({ poster: 'Poster49118 <Poster49118@generic.mail>', subject, name, weak: false })!
+    const a = id('ai-engineer-complete [401/465] - "003 Defining Tools with JSON Schema.mp4" yEnc', '003 Defining Tools with JSON Schema.mp4')
+    const b = id('ai-engineer-complete [422/465] - "006 ai-lesson-4-5-web-search-tools.zip" yEnc', '006 ai-lesson-4-5-web-search-tools.zip')
+    assert.equal(a.key, b.key)
+    assert.equal(a.name, 'ai engineer complete')
+  })
+
   test("a poster's constant tag doesn't make one release of all their uploads", ({ assert }) => {
     const id = (poster: string, subject: string, name: string) => releaseIdentity({ poster, subject, name, weak: false })!
     // [KiLL…] tag on every upload: each album by its stem, its nfo included.