Add fallback negative-case test for track-artist matching

Re-enabling the previously-dead album-aware fallback could in
theory leak false positives if its 0.8 album-title floor were
ineffective. Pin the floor with a clearly-mismatched album hint
("Disney Hits" against "Ray of Light") and assert the search
returns no match. Distinct artist names with no shared words so
the main path actually fails through to the fallback (the prior
draft used "Different Artist" / "Real Artist" which both contain
"Artist" and scored above the main path's threshold, never
reaching the fallback at all).

tests/test_track_artist_matching.py

@@ -151,6 +151,57 @@ def test_search_tracks_attaches_track_artist(db_with_soundtrack: MusicDatabase)
     assert track.artist_name == "Lin-Manuel Miranda"
 
 
+def test_album_aware_fallback_does_not_over_match_wrong_album(tmp_path: Path) -> None:
+    """Fallback must reject when the album-name hint doesn't actually
+    match the row's album. Otherwise re-enabling the previously-dead
+    fallback would surface false positives whenever the search title
+    happens to exist on a different album.
+
+    Album threshold is 0.8 — a clearly different album name like
+    "Some Other Album" must not pass.
+    """
+    db_path = tmp_path / "negative_fallback.db"
+    db = MusicDatabase(database_path=str(db_path))
+
+    conn = db._get_connection()
+    cursor = conn.cursor()
+    cursor.execute(
+        "INSERT INTO artists (id, name, server_source) VALUES (?, ?, ?)",
+        ("ar-y", "Madonna", "plex"),
+    )
+    cursor.execute(
+        "INSERT INTO albums (id, artist_id, title, server_source) VALUES (?, ?, ?, ?)",
+        ("al-y", "ar-y", "Ray of Light", "plex"),
+    )
+    cursor.execute(
+        """
+        INSERT INTO tracks (
+            id, album_id, artist_id, title, track_number, duration,
+            file_path, bitrate, server_source, track_artist
+        ) VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?, ?)
+        """,
+        ("tr-y", "al-y", "ar-y", "Frozen", 1, 200000,
+         "/m/frozen.mp3", 320, "plex", None),
+    )
+    conn.commit()
+    conn.close()
+
+    # Search by a clearly different artist + a totally unrelated album
+    # hint. Main path scores low artist similarity → falls through to
+    # the album-aware fallback. Fallback's 0.8 album-title floor must
+    # reject "Disney Hits" against "Ray of Light".
+    track, _ = db.check_track_exists(
+        title="Frozen",
+        artist="Idina Menzel",
+        confidence_threshold=0.7,
+        album="Disney Hits",
+    )
+    assert track is None, (
+        "fallback must reject mismatched album hints — otherwise "
+        "re-enabling the previously-dead path leaks false positives"
+    )
+
+
 def test_album_aware_fallback_actually_works(tmp_path: Path) -> None:
     """The album-aware fallback path used to TypeError on every row
     because DatabaseTrack(...) was called with kwargs that don't exist