feat(windows): Add Windows companion app (Phase 0-2)
- System tray icon with connection status
- Exec approval dialogs with queue and timeout
- Settings persistence to JSON (%LOCALAPPDATA%\Clawdbot)
- Auto-start on login via Windows Registry
- Notification sounds for approvals and connection events
- WebView2 Control UI embedding
- 23 unit tests passing
- Build scripts and Inno Setup installer template
- Community build guide documentation
Phase 0: Protocol models, WebSocket client, logging
Phase 1: Tray icon, exec approval dialogs, Control UI
Phase 2: Settings, auto-start, sounds, settings UI