Implement comprehensive control panel functionality based on reference patterns:
## New Features
- Icon-only collapsed state with compass positioning
- Expand/drag functionality for repositioning panels
- Bottom-left corner resize with minimum size constraints
- Collapse button returns to original position
- Header toggle for content visibility control
## Technical Improvements
- Enhanced DOM structure with expanded/collapsed states
- Robust event handling with automatic cleanup
- State management for drag, resize, expand operations
- Position restoration system for collapse behavior
- Comprehensive styling system with backdrop effects
## Components Added
- Enhanced ControlBase class with 5 core behaviors
- ContentsControl, StatusControl, EditControl, DebugControl panels
- Component discovery system with TDD implementation
- Legacy DocumentControlsLegacy for backward compatibility
## Testing & Documentation
- Interactive test page for behavior validation
- Comprehensive implementation notes
- TDD test suite with 84 passing tests
- Component listing automation
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Co-Authored-By: Claude <noreply@anthropic.com>