Keep a thumbnail of the finished export in library mode

src/components/CameraControls.tsx

@@ -77,9 +77,24 @@ export default function CameraControls({
           Preview doubles as "back to camera" while in library mode; the flip
           control is hidden then. Anchored to the right edge inside the flex-1
           side zone; small gap keeps it clear of the preview thumbnail without
-          drifting toward the shutter. */}
+          drifting toward the shutter.
+
+          Exports land in the session library, so once library mode has one its
+          thumbnail takes the slot the flip control would have used — that keeps
+          "back to camera" untouched while the finished photo stays reachable
+          (review or trash) after the auto-opened viewer is closed. */}
       <View className="flex-1 flex-row items-center justify-end gap-x-3">
-        {!isLibraryMode && onFlipCamera && (
+        {isLibraryMode ? (
+          lastPhotoUri ? (
+            <TouchableOpacity
+              onPress={onOpenPreview}
+              className="w-12 h-12 rounded-full bg-black/40 border border-zinc-700/70 flex items-center justify-center overflow-hidden"
+              activeOpacity={0.7}
+            >
+              <Image source={{ uri: lastPhotoUri }} style={StyleSheet.absoluteFill} className="object-cover" />
+            </TouchableOpacity>
+          ) : null
+        ) : onFlipCamera ? (
           <TouchableOpacity
             onPress={onFlipCamera}
             className="w-12 h-12 rounded-full bg-black/40 border border-zinc-700/70 flex items-center justify-center"
@@ -87,7 +102,7 @@ export default function CameraControls({
           >
             <RefreshCw size={20} color="#e4e4e7" strokeWidth={1.75} />
           </TouchableOpacity>
-        )}
+        ) : null}
         <TouchableOpacity
           onPress={isLibraryMode && onSwitchToCamera ? onSwitchToCamera : onOpenPreview}
           className="w-12 h-12 rounded-full bg-black/40 border border-zinc-700/70 flex items-center justify-center overflow-hidden"