Add admin-owned broadcast destinations ("community channels"): Discord or
generic webhooks fed straight from release_events by a per-channel watermark
sweep, announcing newly added movies/episodes as grouped digest posts plus
configurable media request lifecycle events (submitted/approved/declined/
fulfilled).
- Extend release_events with a kind discriminator and add a movie
availability spine (movie_availability + kind-keyed
notification_content_seed_state; first full scan seeds silently so
upgrades never flood the movie back catalog)
- Sweep worker reads events by (created_at, id) cursor with batch-window
grouping, per-channel backoff, and auto-disable; request events post
best-effort via new requests.LifecycleNotifier hooks
- Reuse the webhook stack throughout: URL encryption (new AAD namespace),
SSRF guard, embed limits, HMAC signing; shared type/name validation
extracted for both services
- Admin CRUD API under /admin/notifications/server-channels and a Server
Channels section in the notifications admin settings UI
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
