Add rollback procedure documentation and testing scripts (FRE-4808)

- infra/ROLLBACK.md: comprehensive rollback runbook with ECS, Docker Compose,
  database migration, blue-green, and emergency rollback procedures
- infra/scripts/rollback.sh: enhanced ECS rollback with validation, logging,
  health verification, and per-service rollback support
- infra/scripts/rollback-compose.sh: Docker Compose rollback for local/staging
- infra/scripts/rollback-migration.sh: Drizzle migration rollback with
  AWS Secrets Manager integration
- infra/scripts/test-rollback.sh: automated test suite (51 tests)
- Updated infra/README.md to reference ROLLBACK.md

Co-Authored-By: Paperclip <noreply@paperclip.ing>

infra/README.md

@@ -14,7 +14,9 @@
 │   ├── staging/main.tf     # Staging environment config
 │   └── production/main.tf  # Production environment config
 └── scripts/
-    └── rollback.sh         # Manual rollback script
+    ├── rollback.sh             # ECS service rollback (AWS)
+    ├── rollback-compose.sh     # Docker Compose rollback (local/staging)
+    └── rollback-migration.sh   # Database migration rollback
 
 ## Quick Start
 
@@ -75,31 +77,28 @@ terraform apply -var-file=terraform.tfvars.example
 
 ## Rollback
 
-### Automatic (CI/CD)
-The deploy workflow triggers automatic rollback when health checks fail:
-```
-deploy-ecs → health-check (failure) → rollback
-```
+See **[ROLLBACK.md](./ROLLBACK.md)** for the complete rollback runbook, including:
+
+- ECS service rollback (automated + manual)
+- Docker Compose rollback (local / staging)
+- Database migration rollback (Drizzle)
+- Blue-green deployment rollback
+- RDS point-in-time recovery
+- Automated rollback triggers and health checks
+- Emergency rollback runbook
+- Testing checklist
+
+### Quick Reference
 
-### Manual
 ```bash
-# Rollback specific service
-cd infra/scripts
-./rollback.sh staging api
+# ECS service rollback (AWS)
+./infra/scripts/rollback.sh <environment> <service|all> [--verify]
 
-# Rollback all services
-./rollback.sh staging all
-```
+# Docker Compose rollback (local/staging)
+./infra/scripts/rollback-compose.sh <previous_tag>
 
-### Database Migration Rollback
-```bash
-# Run previous migration
-DATABASE_URL=$(aws secretsmanager get-secret-value \
-  --secret-id shieldai-staging-db-password \
-  --query 'SecretString' --output json | jq -r '.host')
-
-npx prisma migrate resolve --applied <migration_name>
-npx prisma migrate deploy
+# Database migration rollback
+./infra/scripts/rollback-migration.sh <environment> [--migration <name>]
 ```
 
 ## GitHub Secrets Required