US-3: Fullstack Composition Module (Sprint 3)

[nnthanh101]

As a product team shipping a React SPA + API backend,
I want a single Terraform module that provisions S3+CloudFront+ALB+ECS+WAF+DNS,
So that I can deploy a complete web application with /api/* routing to ECS and /* to S3.

Acceptance Criteria:

• terraform validate PASSED
• .tftest.hcl tests PASSED (>=2: static-only, fullstack with API)
• Infracost estimate: $30-150/month (100K page views)
• WAFv2 with OWASP Core Rule Set attached to CloudFront
• TLS 1.2+ enforced on all endpoints
• OAC (not OAI) for S3 access
• DNS validated ACM certificate

INVEST Score: I=4 N=4 V=5 E=3 S=3 T=4 = 23/30