Phase 1a of the Discover-to-Sync unification. The mirrored-playlist
refresh handler used to branch per-source through a ~190-line
if/elif chain (Spotify, Spotify public, Deezer, Tidal, YouTube).
Each branch hand-built its own ``extra_data`` JSON for the matched-
data block. With every new source we considered for Sync-page mirror
support (ListenBrainz, Last.fm radio, SoulSync Discovery, iTunes
link), that chain would have grown a new elif.
This commit lifts the per-source logic into the existing adapter
layer and collapses the dispatch to a registry lookup:
- ``core/playlists/sources/deezer.py`` — new adapter so the registry
covers every source the refresh handler previously branched on.
- ``core/playlists/sources/bootstrap.py`` — single helper that builds
a populated registry from injected getter callables. Both
``web_server.py`` boot and the automation test fixtures call it,
so the two construction paths can't drift.
- ``core/playlists/sources/base.py`` — ``to_mirror_track_dict``
projection helper centralises the NormalizedTrack → DB-row
conversion (including the discovered/matched_data and
spotify_hint extra_data shapes the downstream sync + wishlist
consumers already expect).
- Spotify adapter now populates ``extra['discovered']`` + an
``extra['matched_data']`` block when fetching via the authed API,
so Spotify mirrors keep landing pre-discovered (matches the
pre-refactor contract pinned by
``test_spotify_refresh_writes_to_db``).
- Spotify-public adapter populates ``extra['spotify_hint']`` so the
discovery worker can skip its search step and jump straight to
enrichment for the known track ID.
- All artist-name fields now project to first-artist-only across
every adapter — matches the pre-refactor mirror_playlist DB shape
(``t.artists[0]``).
``refresh_mirrored.py`` shrinks ~190 → ~80 lines and keeps:
- the file/beatport unrefreshable-source filter,
- URL extraction from ``description`` via ``require_refresh_url``
for spotify_public + youtube,
- the Spotify-public → authed-Spotify fallback when the user is
signed in (handler-level branch, not in any adapter),
- the Tidal-not-authenticated soft-skip log (skip, not error),
- existing-extra_data preservation across refreshes,
- the ``playlist_changed`` automation event emit on track-set delta.
Test scaffolding:
- ``_build_deps`` in ``tests/automation/test_handlers_playlist.py``
now builds a default registry from the passed clients via
``build_playlist_source_registry``, so existing refresh tests
exercise the same path without per-test changes. New tests cover
Tidal-not-authed soft-skip, Deezer refresh writes plain tracks,
YouTube refresh reads URL from description, and Spotify-public
uses authed Spotify when signed in.
- 4 new adapter tests for Deezer projection +
``to_mirror_track_dict`` (minimal track, Spotify matched_data,
Spotify-public spotify_hint).
- ``playlist_source_registry`` field on ``AutomationDeps`` defaults
to ``None`` so the other 5 automation test files (which don't
exercise refresh_mirrored) keep working unchanged.
220 tests across automation + adapter suites green.