Per code review: ~90 lines of inline gate logic in
``run_full_missing_tracks_process`` was inflating an already-580-
line worker function and was non-testable in isolation. Lifted to
``core/downloads/album_bundle_dispatch.py`` with two entry points:
- ``is_eligible(mode, is_album, album_name, artist_name)`` — pure
predicate, no side effects, easy to assert against. Splits the
gate decision from the resolution + run step so tests can pin
the gate semantics without standing up a plugin.
- ``try_dispatch(...)`` — full flow. Returns True iff the master
worker should stop (gate fired + failed); False = engaged-and-
succeeded OR didn't engage, both fall through to per-track.
State access is now decoupled from ``runtime_state``:
- New ``BatchStateAccess`` Protocol with two methods
(``update_fields``, ``mark_failed``).
- Concrete impl ``_BatchStateAccessImpl`` lives in master.py and
wraps the tasks_lock + dict ops the original inline code did.
- Injected via parameter so the dispatch module never imports
``download_batches`` / ``tasks_lock`` directly.
Same goes for the plugin resolver and config getter — both
injected, so the dispatcher works against any orchestrator /
config implementation (including the in-test fakes).
Behavior unchanged. The master worker call site is now 11 lines
of boilerplate instead of 90 lines of inline conditional. Plugin
contract (``download_album_to_staging`` return dict shape)
unchanged.
- core/downloads/album_bundle_dispatch.py: new module owning the
gate + execution. ~150 lines including docstrings and the
Protocol definition.
- core/downloads/master.py: gate call site shrunk to a single
``if _album_bundle_dispatch.try_dispatch(...): return``. New
``_BatchStateAccessImpl`` class implements the Protocol against
the existing ``download_batches`` dict + ``tasks_lock`` so the
dispatcher gets injected access instead of importing them.
- tests/test_album_bundle_dispatch.py: 16 new tests covering the
pure predicate (album-required, mode allowlist, name validation,
case insensitivity), the resolver-failure fall-through
(plugin missing, plugin lacks method, resolver raises), the
success path returning False so per-track flows, the failure
path returning True with state.mark_failed called, plugin-raise
treated as a normal failure, whitespace stripping on names,
and progress-callback mirroring lifecycle events into batch
state.
