Complete implementation of poka-yoke (mistake-proofing) controls for safe code generation:

1. Path Protection - Domain code safe from accidental overwrites
2. Header Injection - Visual warnings in generated files
3. CODEOWNERS Generation - Automatic team ownership aggregation
4. FMEA Validation - Failure mode validation for packages

- Single interface: ggen.toml
- One command: ggen sync
- All behavior flows from configuration
- No CLI flags required

✅ 30 integration tests - all passing
✅ 100% type coverage
✅ Zero unsafe code
✅ Chicago TDD verified
✅ Production-ready

- Upgraded from v5.0.1 → v5.0.2
- All 14 crates updated
- 3 new integration test suites

See: docs/poka-yoke-quick-reference.md for usage guide