Freeze SAM CD and add Terraform for seahaven-prod (Lambdas, DynamoDB,
EventBridge, alarms) so HCP becomes the sole deploy path. Include prod
secret ARNs in the tfvars example for workspace wiring.
Consolidates front-sla-monitor (Python SAM) and google-user-sync
(JavaScript CDK) into a single Python SAM repo with two Lambdas:
front-sla-monitor and front-user-sync.