Add the shared domain event bus.

crates/bds-core/migrations/2026-07-19-112144-0000_add_notification_project_scope/down.sql

@@ -0,0 +1,3 @@
+DROP INDEX IF EXISTS db_notifications_prune_idx;
+DROP INDEX IF EXISTS db_notifications_unseen_cli_idx;
+ALTER TABLE db_notifications DROP COLUMN project_id;

crates/bds-core/migrations/2026-07-19-112144-0000_add_notification_project_scope/up.sql

@@ -0,0 +1,7 @@
+ALTER TABLE db_notifications ADD COLUMN project_id TEXT;
+
+CREATE INDEX db_notifications_unseen_cli_idx
+    ON db_notifications (from_cli, seen_at, created_at);
+
+CREATE INDEX db_notifications_prune_idx
+    ON db_notifications (seen_at, created_at);