feat: when no slot an album gives one recording is its own, every copy is removed and the album fetched again (M498)

Shnabubula's whole album, one 45-minute file, was filed as both Fading Light
and Looking for Answers. Neither slot fits, so wrongSlots had nothing to keep
and held the group. Every copy now goes when each is clearly another song's;
a copy near its slot still holds the group.

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

internal/library/duplicate_resolve_test.go

@@ -405,6 +405,27 @@ func TestResolveDuplicates_RemovesACopyFromAnotherSongsSlot_Integration(t *testi
 	}
 }
 
+// One recording filling two slots whose songs are both clearly something else
+// (Shnabubula's whole album in one file): both copies go, nothing is kept.
+func TestResolveDuplicates_RemovesEveryCopyWhenNoSlotIsTheirs_Integration(t *testing.T) {
+	f := newOneAlbumFixture(t, "acoustic", "Void", "Reach")
+	seedTrackList(t, f.pool, f.album, map[string]int{"Void": 282000, "Reach": 421000})
+	res, err := ResolveDuplicates(context.Background(), f.pool, nil, "", true)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if res.WrongFiles != 2 || exists(f.aPath) || exists(f.bPath) {
+		t.Fatalf("result %+v, void exists %v, reach exists %v; want both copies removed",
+			res, exists(f.aPath), exists(f.bPath))
+	}
+	if status, _, _, auto := (resolveFixture{pool: f.pool, groupID: f.groupID}).group(t); status != "merged" || !auto {
+		t.Errorf("group = (%s, auto=%v), want settled by the resolver", status, auto)
+	}
+	if n := auditCount(t, f.pool, "duplicate_wrong_file", f.groupID); n != 1 {
+		t.Errorf("wrong-file audit rows = %d, want 1", n)
+	}
+}
+
 // An album whose track list the catalogue never read: the resolver asks for
 // it, once, and decides with what comes back.
 func TestResolveDuplicates_FetchesAMissingTrackList_Integration(t *testing.T) {