Add example story for User Email Validation TDD workflow:
- Complete story with acceptance criteria in Gherkin format
- Technical requirements and test plan with test IDs
- TDD phase progress tracking (currently red)
- Implementation tasks for Dev agent
- Directory structure for JS and Python demo implementations
This demo story provides teams with a practical example to reproduce
the red-green-refactor TDD cycle using BMAD framework and methodology.
6f109064e6