reconcile_playlist read the existing playlist's track ids with str(t.id), but NavidromeTrack
exposes the Subsonic song id as .ratingKey and has NO .id attribute (append_to_playlist already
reads ratingKey — reconcile was the straggler). So current_ids came back EMPTY every time:
plan_playlist_reconcile saw an 'empty' playlist, re-added the entire matched set, and removed
nothing. Result: the playlist grew by the full track count on every sync (warl0ck: 5 songs, one
removed -> 9), in reconcile mode and whenever reconcile is the active mode.
Fix: read current ids via ratingKey, matching append_to_playlist.
Verified: tests/test_navidrome_reconcile.py drives the real reconcile_playlist with a stubbed
server — reverting the one-char change flips 3 tests red (they show it re-adding all 4 tracks),
the fix flips them green. Covers no-op resync, a removed track (remove, don't re-add all), and an
added track (append once).
