Identity: a set's number before yEnc is no size; names after an arrow

- The unit-less size before the closing yEnc ('"x.mp3" - 8123 yEnc') took
  the set number in 'Newstar Destiny I set 1 [1 of 60] "destiny-001-001.jpg"
  yEnc' once the quotes were gone: 97 sets of 60 were one release. A number
  of fewer than 4 digits after a word stays.
- unquotedName also cuts after "-> " ("… -> [0001 of 0076] ->
  Exclusive-tgirls_000000-lg.jpg"): the arrow was part of the file name.

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

lib/headers/subject.ts

@@ -63,7 +63,9 @@ export function unquotedName(beforeCounter: string): string | null {
     // is the album, the same for every track (LOG.md 2026-10-11 (10)); else after the last " - ".
     const track = / - \d{1,3} - /.exec(text)
     const dash = track ? track.index : text.lastIndexOf(' - ')
-    const cut = Math.max(bracket === -1 ? 0 : bracket + 2, dash === -1 ? 0 : dash + 3)
+    // Or after an arrow ("… -> [0001 of 0076] -> Exclusive-tgirls_000000-lg.jpg").
+    const arrow = text.lastIndexOf('-> ')
+    const cut = Math.max(bracket === -1 ? 0 : bracket + 2, dash === -1 ? 0 : dash + 3, arrow === -1 ? 0 : arrow + 3)
     const name = text.slice(cut).trim()
     return name && EXTENSION.test(name) ? name : null
   }