C360 endpoint cutover to production

The QA C360 gateway froze after 07-25, so the nightly acquisition job has been writing stale numbers while still reporting success. This cutover points the job at the production endpoint and production client-id.

Change: update the client-id in Secrets Manager and register new ECS task-def revisions adding the C360_URL variable. Environment and secret only. No schema change, no frontend deploy.

Prerequisites: the production gateway must allowlist our egress IPs 3.93.139.220 and 3.93.243.176. Cutover should happen before Sunday 08-09, after which one week of data becomes unrecoverable.

Rollback: re-register the prior task-def revision and restore the old client-id.

Dependency: AWS writes require Ajay, as our role is read-only. Full runbook held separately.