Hardening fixes: Camera cancellation, Android memory optimization, action button throttling

src/screens/CameraScreen.tsx

@@ -92,6 +92,7 @@ export default function CameraScreen({
   const usbCameraRef = useRef<UsbCameraRef>(null);
   const expoCameraRef = useRef<any>(null);
   const burstTimerRef = useRef<any>(null);
+  const isCancelledRef = useRef<boolean>(false);
 
   // Reanimated countdown pulse animation
   const scale = useSharedValue(1);
@@ -195,6 +196,7 @@ export default function CameraScreen({
 
   // Cancel capture process
   const handleLocalCancel = async () => {
+    isCancelledRef.current = true;
     if (burstTimerRef.current) clearTimeout(burstTimerRef.current);
     
     // Clean up any temp files from a partially completed burst
@@ -208,6 +210,8 @@ export default function CameraScreen({
     
     setCountdown(countdownDuration);
     setIsCapturing(false);
+    setIsBurstWaiting(false);
+    setHasStarted(false);
     setBurstIndex(0);
     setBurstUris([]);
     setShowBurstIndicator('');
@@ -229,6 +233,7 @@ export default function CameraScreen({
   }, [countdownDuration, isIdle]);
 
   const startCountdown = () => {
+    isCancelledRef.current = false;
     let timer: any;
     let count = countdownDuration;
 
@@ -281,7 +286,7 @@ export default function CameraScreen({
         if (expoCameraRef.current) {
           const photo = await expoCameraRef.current.takePictureAsync({
             quality: 0.7, // Lower quality slightly to reduce file size
-            skipProcessing: false, // Ensure correct orientation
+            skipProcessing: Platform.OS === 'android', // Prevent memory crash on Android
           });
           capturedUri = photo.uri;
         } else {
@@ -289,6 +294,12 @@ export default function CameraScreen({
         }
       }
 
+      // If user cancelled while the camera promise was processing, abort before side-effects
+      if (isCancelledRef.current) {
+        console.log('Capture cancelled by user during processing.');
+        return;
+      }
+
       // Instead of manipulating the image and risking an OOM or BitmapFactory crash,
       // we directly use the captured photo and rely on React Native's Image component
       // to safely downsample it during rendering via resizeMethod="resize".