fix: add message type validation to prevent integration test interference

- Add check to ensure message event handler only processes relevant messages
- Prevents ModeSelector from interfering with integration test message handling
- This should fix the intermittent integration test timeouts

webview-ui/src/components/chat/ModeSelector.tsx

@@ -165,6 +165,9 @@ export const ModeSelector = ({
 	React.useEffect(() => {
 		const handler = (event: MessageEvent) => {
 			const message = event.data
+			// Only handle messages that are specifically for mode export/import
+			if (!message || typeof message !== "object") return
+
 			if (message.type === "exportModeResult") {
 				setIsExporting(null)
 				if (!message.success) {