Added comprehensive draggable window system with the following features:
🪟 **DraggableWindow Component**:
- Full drag and drop functionality with title bar dragging
- Window resizing from all edges and corners
- Maximize/minimize/close window controls
- Double-click title bar to maximize/restore
- Auto position adjustment to prevent off-screen windows
- Windows-style blue gradient title bar
📁 **FileViewer Component**:
- Multi-format file support (text, code, images, videos, audio)
- Syntax highlighting distinction for code files
- Editable text files with real-time content tracking
- File metadata display (size, modified date, permissions)
- Save and download functionality
- Unsaved changes indicator
🎯 **WindowManager System**:
- Multi-window support with proper z-index management
- Window factory pattern for dynamic component creation
- Focus management - clicking brings window to front
- Smart window positioning with auto-offset
- Memory leak prevention with proper cleanup
🔗 **FileWindow Integration**:
- SSH file loading with error handling
- Auto-detect editable file types
- Real-time file saving to remote server
- Download files as binary blobs
- Loading states and progress feedback
✨ **User Experience**:
- Double-click any file to open in draggable window
- Multiple files can be open simultaneously
- Windows behave like native Windows Explorer
- Smooth animations and transitions
- Responsive design that works on all screen sizes
This transforms the file manager from a basic browser into a full
desktop-class application with native OS window management behavior.