- Add CodeMirror editor with syntax highlighting for JavaScript and Python
- Add 8 starter templates (4 JS, 4 Python) for common tool patterns
- Add inline documentation panel with language-specific guidance
- Add tool testing UI to run tools with sample inputs before saving
- Add Python tool execution via backend API with 30s timeout
- Add POST /api/v1/tools/execute endpoint for backend tool execution
- Update Dockerfile to include Python 3 for tool execution
- Bump version to 0.4.0
