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>

edge/src/names.rs

@@ -579,10 +579,17 @@ pub fn release_identity(poster: &str, subject: &str, name: &str) -> Release {
     let image = test(&IMAGE, name);
     // The poster's constant tag outside the quotes: the file's stem says which upload it is (not for images and audio).
     // Not for numbered items of a set ("003 Defining Tools with JSON Schema.mp4"): /^\d{1,3}[ ._-]/.
+    // /^(?:[A-Z]{1,5}\d{2,6}[-_ ])?\d{1,3}[ ._-]/: also after a disc code ("SC8367-12 - …").
     let numbered = {
         let b = stem.as_bytes();
-        let digits = b.iter().take_while(|c| c.is_ascii_digit()).count();
-        (1..=3).contains(&digits) && matches!(b.get(digits), Some(b' ' | b'.' | b'_' | b'-'))
+        let index_at = |at: usize| {
+            let digits = b[at..].iter().take_while(|c| c.is_ascii_digit()).count();
+            (1..=3).contains(&digits) && matches!(b.get(at + digits), Some(b' ' | b'.' | b'_' | b'-'))
+        };
+        let letters = b.iter().take_while(|c| c.is_ascii_uppercase()).count();
+        let code_digits = b[letters..].iter().take_while(|c| c.is_ascii_digit()).count();
+        let code = (1..=5).contains(&letters) && (2..=6).contains(&code_digits) && matches!(b.get(letters + code_digits), Some(b'-' | b'_' | b' '));
+        index_at(0) || (code && index_at(letters + code_digits + 1))
     };
     let tag = !image && !numbered && !test(&AUDIO, name) && describes(&stem) && !looks_random(&stem) && is_poster_tag(&remainder, &stem);
     let prefix = if image { image_prefix(&stem) } else { String::new() };
@@ -1085,6 +1092,8 @@ mod numbered_tests {
         let b = release_identity(poster, r#"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_eq!(a.key, b.key);
         assert_eq!(a.name, "ai engineer complete");
+        let sc = |t: &str| release_identity("p", &format!("Spotlight - 83xx's [16/19] - \"{t}.zip\" yEnc"), &format!("{t}.zip"));
+        assert_eq!(sc("SC8367-12 - Wynette, Tammy - Singing My Song").key, sc("SC8367-13 - Jones, George - He Stopped Loving Her Today").key);
     }
 }