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>

edge/src/names.rs

@@ -360,6 +360,11 @@ fn strip_number_before_yenc(s: &str) -> String {
     if digits_start > 0 && (b[digits_start - 1].is_ascii_alphanumeric() || b[digits_start - 1] == b'_') {
         return s.to_string();
     }
+    // A short number after a word is a set's ("… set 1 [1 of 60] "destiny-001-001.jpg" yEnc"), not a size.
+    let word_before = b[..digits_start].iter().rev().find(|&&c| !js::is_space(c as char)).is_some_and(|c| c.is_ascii_alphanumeric());
+    if digits_end - digits_start < 4 && word_before {
+        return s.to_string();
+    }
     format!("{}{}", &s[..digits_start], &s[digits_end..])
 }
 
@@ -1273,7 +1278,14 @@ mod image_set_tests {
         let a = release_identity(mb, r#"Herb Ernst@256 - NMR -[07/17] "Herb Ernst - Dreamflight II - 05 - The Light of Forever.mp3" - 8123 yEnc"#, "Herb Ernst - Dreamflight II - 05 - The Light of Forever.mp3");
         let b = release_identity(mb, r#"Herb Ernst@256 - NMR -[08/17] "Herb Ernst - Dreamflight II - 06 - Other.mp3" - 9001 yEnc"#, "Herb Ernst - Dreamflight II - 06 - Other.mp3");
         assert_eq!(a.key, b.key);
-        for s in [r#"x - "a.mp3" - 8123 yEnc"#, "a8123 yEnc", "-8123 yEnc ", "yEnc"] {
+        let destiny = |set: u32, i: u32| {
+            let name = format!("destiny-{set:03}-{i:03}.jpg");
+            release_identity("p", &format!(r#"Newstar Destiny I set {set} [{i} of 60] "{name}" yEnc"#), &name)
+        };
+        assert_eq!(destiny(1, 1).key, destiny(1, 2).key);
+        assert_ne!(destiny(1, 1).key, destiny(63, 34).key);
+        assert_eq!(destiny(63, 34).name, "Newstar Destiny I set 63");
+        for s in [r#"x - "a.mp3" - 8123 yEnc"#, "a8123 yEnc", "-8123 yEnc ", "yEnc", r#"set 1 [1 of 60] "x.jpg" yEnc"#, "Album 12 yEnc", "Album 1234 yEnc"] {
             assert_eq!(super::subject_remainder(s), super::subject_remainder_re(s), "{s}");
         }
         assert!(random_poster("SOFZRw1-OTEd@EEFUbh.srG"));