docs: reorganize documentation for better readability

Simplify CLAUDE.md from 1,386 lines to 205 lines by extracting
detailed content into focused reference documents. This improves
agent comprehension and developer navigation.

Changes:
- Streamlined CLAUDE.md to essential workflow and quick reference
- Created docs/COMMANDS.md - Complete command reference (170 lines)
- Created docs/CONTRIBUTING.md - Git workflow and PR process (250 lines)
- Created docs/TESTING.md - Test strategy and CI/CD (290 lines)
- Created docs/EXAMPLES.md - Usage examples (450 lines)
- Created docs/ARCHITECTURE.md - Design decisions (440 lines)
- Created docs/TROUBLESHOOTING.md - Common issues (380 lines)

Benefits:
- 85% reduction in core context size
- Focused instructions with on-demand details
- Standard OSS structure (CONTRIBUTING.md)
- Better organization and maintainability

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

Author: platinummonkey