fix(scheduler): allow 'starting' and 'stopping' statuses in DB

The scheduler tick loop updates a schedule's status to 'starting' and 'stopping'
in the database while it initiates the API calls to the recorder container. The
original CHECK constraint in recorder_schedules rejected these two statuses,
causing the scheduler to crash on constraint violation and never start the job.

services/mam-api/src/db/migrations/035-alter-schedule-status-constraint.sql

@@ -0,0 +1,7 @@
+-- Add 'starting' and 'stopping' to recorder_schedules status check constraint
+
+ALTER TABLE recorder_schedules DROP CONSTRAINT recorder_schedules_status_check;
+
+ALTER TABLE recorder_schedules
+  ADD CONSTRAINT recorder_schedules_status_check
+  CHECK (status IN ('pending','running','completed','failed','cancelled','starting','stopping'));