Slice 2 of #392 — wires the first producers onto the bus that slice 1
built. After this commit, an SSE subscriber sees real events fire:
- track.liked / track.unliked when the user toggles the heart on a track
(handleLikeTrack / handleUnlikeTrack). Album + artist like events
intentionally deferred — they're symmetric trivial follow-ups but the
operator's primary like surface is tracks.
- request.status_changed when a Lidarr request is created, cancelled,
approved, or rejected. Auto-approve will fire twice (pending then
approved) in rapid succession, which is semantically correct; client
invalidation handles that fine.
Events are user-scoped via row.UserID so admin approve/reject route to
the requester, not the admin acting. Helpers live in events_publish.go
so the wire shape (kind names, payload keys) stays in one place — future
producers in slice 3 reuse the same pattern.
events_publish.go is no-op when h.eventbus is nil so tests that
construct handlers without a bus continue to pass.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
