Fix final 4 resilience edge cases

src/screens/PreviewScreen.tsx

@@ -289,8 +289,8 @@ export default function PreviewScreen({
     }
   };
 
-  // Auto-save and exit
-  const handleExit = useCallback(async () => {
+  const handleExitRef = useRef<() => void>();
+  handleExitRef.current = async () => {
     if (idleTimerRef.current) clearTimeout(idleTimerRef.current);
     if (!mountedRef.current) return;
     if (isProcessing) return;
@@ -319,15 +319,20 @@ export default function PreviewScreen({
       setIsProcessing(false);
       state.onReset();
     }
-  }, []); // Stable reference
+  };
+
+  // Auto-save and exit
+  const handleExit = useCallback(async () => {
+    if (handleExitRef.current) handleExitRef.current();
+  }, []);
 
   // Idle timer logic
   const resetIdleTimer = useCallback(() => {
     if (idleTimerRef.current) clearTimeout(idleTimerRef.current);
     idleTimerRef.current = setTimeout(() => {
-      handleExit();
+      if (handleExitRef.current) handleExitRef.current();
     }, 60000);
-  }, [handleExit]);
+  }, []);
 
   useEffect(() => {
     resetIdleTimer();