feat: Add TDD infrastructure and scaffold files
- Create TDD tasks: write-failing-tests.md, tdd-implement.md, tdd-refactor.md
- Add TDD story template with frontmatter metadata tracking
- Implement TDD-specific Definition of Done checklist
- Create TDD workflow orchestration (Red-Green-Refactor cycle)
- Add TDD prompts for QA (Red), Dev (Green), and Refactor phases
- Configure test runner auto-detection for JS/TS, Python, Go, Java, .NET, Ruby
- Update core-config.yaml with TDD settings (disabled by default)
- Add story frontmatter schema with TDD metadata fields
All files pass linting and formatting checks.
Backward compatible - TDD disabled by default (tdd.enabled: false)
36ca3c1bfa