workflow-build-feature — End-to-End Feature Build

One command that runs the full feature loop. Don't skip phases — each gate catches a class of defects the next phase can't.

Phase sequence

1. SPEC        → workflow-spec-tdd (contract, plan, RED test)
2. BUILD       → implement against the spec (GREEN)
3. UNIT TEST   → test-unit (edge cases, mocks, coverage)
4. SMOKE       → test-playwright (drive the live app as a real user, fix pain points)
5. PR          → workflow-pr (create PR with test evidence)