feat(notifications): include federated chat messages and invitations

backend/db/migrations/0083_collaboration_notifications.sql

@@ -0,0 +1,7 @@
+INSERT INTO notifications_event_types (event_key, display_name, description, category, allowed_channels) VALUES
+('collaboration.message.new', 'Zusammenarbeit: Chatnachrichten', 'Neue Nachrichten in freigegebenen Unterräumen und föderierten Chats.', 'collaboration', '["inapp","email","push"]'),
+('collaboration.room.invited', 'Zusammenarbeit: Einladungen', 'Persönliche Einladungen in freigegebene Unterräume und föderierte Chats.', 'collaboration', '["inapp","email","push"]')
+ON CONFLICT (event_key) DO NOTHING;
+--> statement-breakpoint
+CREATE INDEX notifications_collaboration_queued ON notifications_items(created_at)
+WHERE status='queued' AND event_type IN ('collaboration.message.new','collaboration.room.invited');