[E-3.11] Add E2E test for deployment pipeline

**Chore** | P2 | Risk: Low | Effort: M | Release: 1.0.0
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Verify `deploy:check` command works end-to-end with real environment configuration.

**Acceptance criteria:**
- E2E test executes deploy:check against real config
- Test verifies all checks run and report correctly
- Test covers pass and fail scenarios