feat(workflow): add chain-loaded workflow planning and TDD planning skills

- Introduced `workflow-plan` skill with a 6-phase planning workflow including mode routing and conflict detection.
- Added `workflow-tdd-plan` skill featuring a 7-phase TDD planning workflow with Red-Green-Refactor task generation.
- Created `workflow-test-fix` skill for a 5-phase test generation and iterative execution pipeline.
- Implemented a unified launcher for Claude Code with workflow switching capabilities.
- Added chain visualizer for terminal ASCII visualization of chain topology and progress.

Author: catlog22