New "Deezer" tab on sync page shows authenticated user's playlists,
identical to the Spotify tab pattern — same card layout, details
modal with track list, sync button, and download missing tracks
flow. Existing URL import renamed to "Deezer Link" tab (unchanged).
Backend: get_user_playlists() and get_playlist_tracks() on the
download client fetch via public API with ARL session cookies.
Album release dates batch-fetched for $year template variable.
Three new endpoints: arl-status, arl-playlists, arl-playlist/<id>.
Frontend: cards use Spotify-identical HTML structure with live sync
status, progress indicators, and View Progress/Results buttons.
Downloads reuse openDownloadMissingModal with zero modifications.
Track data cached on first open, instant on subsequent clicks.
Deezer client imports config_manager locally in __init__ and stores
it as self._config, unlike the other clients which import at module
level. The allow_fallback line was referencing the wrong name.
Each streaming source (Tidal, Qobuz, HiFi, Deezer) now has an "Allow
quality fallback" checkbox in Settings. When disabled, the source only
tries the exact quality selected — if unavailable, it skips and lets
the orchestrator try the next source. Default is ON (current behavior).
