feat: video rips and stray copies handle themselves (M498 #5439)

- The resolver also merges cross-release and mismatch groups where Lidarr
  maps exactly one copy: the others fulfil nothing, so removing them opens no
  hole (D-a rule 1). That covers a rip beside the clean copy on another
  release and a wrong-file import Lidarr holds unmapped. With two or more
  mapped copies each fulfils its own release and nothing is removed.
- A track whose file name carries a video-rip marker is held back from radio
  and the system mixes (tracks.source_verdict, migration 0077). It still plays
  when chosen. A renamed file is released; the operator's "fine" sticks.
- Suspect sources shows what was done to each track, with "This one is fine"
  and "Hold back again" (PUT /api/admin/library/suspect-sources/{id}).
- The Liked list prefers a copy that is not held back.

Replacing a rip that has no clean copy is left for the operator to decide.

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

internal/playlists/song_copies_test.go

@@ -0,0 +1,49 @@
+package playlists
+
+import (
+	"context"
+	"testing"
+
+	"github.com/jackc/pgx/v5/pgtype"
+
+	"git.fabledsword.com/bvandeusen/minstrel/internal/db/dbq"
+)
+
+// A mix holds a song once (M498 #5438) and never a held-back video rip
+// (#5439): of a single and its album cut, the better-ranked copy stays; a rip
+// is left out and the next copy of its song takes the place.
+func TestOneCopyPerSong_Integration(t *testing.T) {
+	pool := newPool(t)
+	ctx := context.Background()
+	q := dbq.New(pool)
+	single := seedTrack(t, pool, "copies-single", "copies-artist")
+	albumCut := seedTrack(t, pool, "copies-album-cut", "copies-artist")
+	rip := seedTrack(t, pool, "copies-rip", "copies-artist")
+	clean := seedTrack(t, pool, "copies-clean", "copies-artist")
+	other := seedTrack(t, pool, "copies-other", "copies-artist")
+	for _, pair := range [][]pgtype.UUID{{single.ID, albumCut.ID}, {rip.ID, clean.ID}} {
+		if _, err := q.LinkTracksAsSong(ctx, pair); err != nil {
+			t.Fatal(err)
+		}
+	}
+	if _, err := pool.Exec(ctx, `UPDATE tracks SET source_verdict = 'suspect' WHERE id = $1`, rip.ID); err != nil {
+		t.Fatal(err)
+	}
+
+	in := []rankedCandidate{
+		{TrackID: single.ID}, {TrackID: rip.ID}, {TrackID: albumCut.ID}, {TrackID: other.ID}, {TrackID: clean.ID},
+	}
+	out, err := oneCopyPerSong(ctx, q, in)
+	if err != nil {
+		t.Fatal(err)
+	}
+	want := []pgtype.UUID{single.ID, other.ID, clean.ID}
+	if len(out) != len(want) {
+		t.Fatalf("got %d tracks, want %d", len(out), len(want))
+	}
+	for i, w := range want {
+		if out[i].TrackID != w {
+			t.Errorf("position %d = %s, want %s", i, uuidString(out[i].TrackID), uuidString(w))
+		}
+	}
+}