Add deep diagnostic logging for ViewShot failures

src/screens/PreviewScreen.tsx

@@ -204,12 +204,17 @@ export default function PreviewScreen({
   // ── Capture the final image ──
   const captureComposite = async (fallbackPhoto: string = currentPhoto) => {
     try {
+      logger.log(`captureComposite started. Has ViewShot ref: ${!!viewShotRef.current}`);
       if (viewShotRef.current) {
-        return await viewShotRef.current.capture();
+        logger.log('Executing viewShotRef.current.capture()...');
+        const uri = await viewShotRef.current.capture();
+        logger.log(`ViewShot successfully generated collage URI: ${uri}`);
+        return uri;
       }
+      logger.log('[WARNING] viewShotRef.current was null, falling back to raw photo.');
       return fallbackPhoto;
     } catch (e: any) {
-      logger.error('Failed to capture composite', e);
+      logger.error('Failed to capture composite (ViewShot crashed)', e?.message || e);
       return fallbackPhoto;
     }
   };