feat: Jellyfin/Plex auto-import via watch queue

Webhook ingestion from media servers — movies land in a pending
watch queue, user rates and confirms to create diary entries.

- domain: WatchEvent, WebhookToken models, MediaServerParser port
- adapters: jellyfin + plex parser crates, SQLite + Postgres repos
- application: ingest/confirm/dismiss/cleanup use cases, token mgmt
- presentation: webhook endpoints (bearer + query param auth),
  watch queue + integrations settings HTML pages, OpenAPI docs
- worker: WatchEventCleanupJob (daily, 30d retention)

Movie resolution deferred to confirm — single canonical path
through log_review for enrichment, poster fetch, federation.

crates/adapters/nats/src/subject.rs

@@ -15,6 +15,7 @@ pub fn event_to_subject(prefix: &str, event: &DomainEvent) -> String {
         DomainEvent::FollowAccepted { .. } => "follow.accepted",
         DomainEvent::BackfillFollower { .. } => "backfill.follower",
         DomainEvent::FederationDeliveryRequested { .. } => "federation.delivery.requested",
+        DomainEvent::WatchEventIngested { .. } => "watch.event.ingested",
     };
     format!("{prefix}.{suffix}")
 }