feat(CallScreen): enhance video call functionality and UI updates

- Integrated video call support by adding local and remote video stream handling.
- Implemented state management for video track detection in both local and peer streams.
- Updated UI to conditionally render video components based on the presence of video tracks.
- Added video toggle functionality to enable or disable local video during calls.
- Enhanced incoming call modal to display call type (voice or video).
- Refactored call store to manage call types and video state more effectively.

src/components/call/IncomingCallModal.tsx

@@ -132,7 +132,9 @@ const IncomingCallModal: React.FC = () => {
           <Text style={styles.callerName} numberOfLines={1}>
             {incomingCall.callerName || '未知用户'}
           </Text>
-          <Text style={styles.callType}>来电通话</Text>
+          <Text style={styles.callType}>
+            {incomingCall.callType === 'video' ? '视频通话' : '语音通话'}
+          </Text>
         </View>
 
         {/* Bottom controls */}