Add minimum 60% title similarity gate to match_recording() — prevents
artist bonus + MB score from pushing unrelated titles past the confidence
threshold (e.g. "Sweet Surrender" matching "Answers" by same artist).
New MBID Mismatch Detector repair job reads embedded MusicBrainz recording
IDs from audio files, verifies them against the MusicBrainz API, and flags
tracks where the MBID points to a different song. Fix action strips the bad
MBID tag so media servers like Navidrome fall back to correct file tags.
