GCP-06: Multi-Region Cloud Run — Eliminate SPOF

Deploy Cloud Lu to multiple regions with Global Load Balancer for automatic failover. Current pain: Single container in europe-west1. If region has issues, everything stops. Architecture: 1. Primary: europe-west1 (min_instances=1, always-on) 2. Secondary: us-central1 (min_instances=0, scales on failover) 3. Global External Application Load Balancer with health checks 4. SSL managed cert for cloud-lu.c8platform.com 5. Stateless design required (depends on GCP-02) Deliverables: - Terraform for GLB + backend services + health checks + SSL - Cloud Run deploy for both regions - DNS setup - Failover test procedure Logical dependency: GCP-02 (stateless daemon) first Target: c8-infra/terraform/modules/multi-region/