fix: a duplicate fold never deletes a lossless copy for a lossy one, nor folds two versions (M498)

The first album-copy fold pass on 2026-10-20 removed five FLACs (Måneskin
Rush!, Weezer 2016) in favour of mp3s whose only edge was a recording MBID,
and an explicit "Suite-Pee" for its clean version. ProposeSurvivor now ranks
lossless before tag fit; tag fit still outranks file size, which is what the
Humanz rips needed. The fold keys copies by their version words (title and
file name), so a clean, live or instrumental copy holding the same title tag
is linked, not folded.

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

internal/library/duplicate_resolve.go

@@ -244,7 +244,10 @@ func ResolveDuplicatesWith(
 
 // foldAlbumCopies merges, in each cross-release group, the extra copies one
 // album holds of the song into the best of that album's copies: the one that
-// is not a video rip when only one is not, else ProposeSurvivor's choice. The
+// is not a video rip when only one is not, else ProposeSurvivor's choice.
+// Copies whose title or file name name different versions (versionWords) are
+// not folded: "Suite-Pee" and "Suite-Pee (Clean Version)" carried one title tag
+// on 2026-10-20, and the explicit copy went. The
 // copies on other releases stay and are linked as one song. At most budget
 // copies go. It returns how many went and the songs they were, and drops them
 // from their groups.
@@ -260,7 +263,8 @@ func foldAlbumCopies(
 		}
 		onAlbum := map[string][]int{}
 		for i, m := range g.members {
-			k := syncpkg.FormatUUID(m.AlbumID) + "\x00" + MatchTitleKey(m.Title, m.ArtistName)
+			k := syncpkg.FormatUUID(m.AlbumID) + "\x00" + MatchTitleKey(m.Title, m.ArtistName) +
+				"\x00" + versionWords(m.Title, m.FilePath)
 			onAlbum[k] = append(onAlbum[k], i)
 		}
 		gone := map[int]bool{}