An upload spread over groups is one release

FTD posts one upload's files to different groups ("Knowsum-Loops_Are_My_
Religion-WEB-2026-FTD": par2 and part1 to a.b.music.misc, part2 to
a.b.sounds.music, each article in one group only; releases 81825221 and
81825412): the catalog matched a chunk only to releases of its own
group. A chunk without one there now joins a release of its key in
another group whose window is within 3 hours, when none of its file
names are in that release yet; a post of the same files to another group
(other message-ids, same names) stays a release of its own, or its NZB
would hold every file twice. Functional tests for both.

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

tests/functional/batch_store.spec.ts

@@ -128,6 +128,14 @@ test.group('BatchStore', (group) => {
     assert.equal(rows[0].identity_key, rows[1].identity_key)
   })
 
+  test('an upload spread over groups (other files in another group) is one release', async ({ assert }) => {
+    await storeIn(GROUP, 1, upload(10, 'Some.Album-WEB-2026-FTD.part1.rar', 2, 'Some.Album-WEB-2026-FTD [2/3]', '2026-10-05T10:00:00Z'))
+    await storeIn('alt.binaries.other', 1, upload(10, 'Some.Album-WEB-2026-FTD.part2.rar', 2, 'Some.Album-WEB-2026-FTD [3/3]', '2026-10-05T10:00:30Z', 'alt.binaries.other'))
+    const rows = await releasesOf()
+    assert.lengthOf(rows, 1)
+    assert.equal(rows[0].files, 2)
+  })
+
   test('a release key taken meanwhile by another group\'s writer is skipped for the next number', async ({ assert }) => {
     await storeIn(GROUP, 1, upload(10, 'Some.Show.S01E01.1080p.mkv', 2, 'Some.Show.S01E01.1080p [1/1]', '2026-10-05T10:00:00Z'))
     const [first] = await releasesOf()