Add user-specific API endpoints and MCP configuration

- Added /api/user/* endpoints for authenticated users to access their own configurations
- Admin users get access to global + user configs, regular users get user-only
- Global tokens from aisbf.json have full access to all configurations
- Enhanced MCP with user-specific tools for authenticated users
- Updated user dashboard with comprehensive API endpoint documentation
- Updated README.md, DOCUMENTATION.md with new endpoint documentation
- Updated CHANGELOG.md with new features
- Bumped version to 0.9.1