fix(library): optimize image scanning, fast raw preview extraction and lazy thumbnail loading

docker/frontend/src/App.tsx

@@ -936,6 +936,24 @@ export function Workspace() {
     void forgetPhoto();
   }, [clearPreview]);
 
+  // Clean up Object URLs when App unmounts (e.g. SPA navigation to Library)
+  useEffect(() => {
+    return () => {
+      setPreviewUrl((prev) => {
+        if (prev) URL.revokeObjectURL(prev);
+        return null;
+      });
+      setCompareUrl((prev) => {
+        if (prev) URL.revokeObjectURL(prev);
+        return null;
+      });
+      setSource((prev) => {
+        if (prev) URL.revokeObjectURL(prev.url);
+        return null;
+      });
+    };
+  }, []);
+
   // What the phone app gets from the OS geocoder, the browser has no twin of,
   // so the name behind a coordinate comes from the API. Fire and forget: the
   // stamp is already readable without it, and a name that arrives late (or not