- Add VoIP types: CallState, CallType, CallDirection, SimpleCall, CallCallbacks
- Add VoIP state management to Matrix store with place/answer/reject/hangup methods
- Add mic/camera mute toggle functionality
- Create CallView component for active calls with video streams
- Create IncomingCallDialog component for incoming call notifications
- Enable call buttons in RoomHeader (DMs only)
- Integrate call components into chat page