fix: address PR #264 review issues

- Fix connectDesktopStream silently dropping RTCPeerConnection and rtcConfig options (client.ts)
- Fix DesktopViewer useEffect dependency causing reconnect loop (store callbacks in refs)
- Fix TOCTOU race condition in DesktopRecordingManager::start() (merge lock scope)
- Fix incomplete cursor bounds check in composite_cursor_region (add right/bottom checks)
- Add DesktopViewer to react-components.mdx documentation
- Remove hardcoded visual styles from DesktopViewer (make unstyled by default per sdks/CLAUDE.md)
- Export DesktopViewerClassNames type for consumer styling

Co-Authored-By: Claude Haiku 4.5 <noreply@anthropic.com>

sdks/typescript/src/client.ts

@@ -2005,7 +2005,7 @@ export class SandboxAgent {
   }
 
   connectDesktopStream(options: DesktopStreamSessionOptions = {}): DesktopStreamSession {
-    return new DesktopStreamSession(this.connectDesktopStreamWebSocket(options));
+    return new DesktopStreamSession(this.connectDesktopStreamWebSocket(options), options);
   }
 
   private async getLiveConnection(agent: string): Promise<LiveAcpConnection> {