Refresh local videos on each listing request

server/index.js

@@ -132,6 +132,8 @@ app.get('/api/favorites', (_request, response) => {
 });
 
 app.get('/api/local-videos', async (_request, response) => {
+  response.set('Cache-Control', 'no-store');
+
   if (!LOCAL_VIDEOS_ROOT) {
     response.json({ enabled: false, videos: [] });
     return;
@@ -658,9 +660,12 @@ function getLocalVideosRealRoot() {
   }
 
   if (!localVideosRealRootPromise) {
-    localVideosRealRootPromise = fs.realpath(LOCAL_VIDEOS_ROOT).catch((error) => {
-      localVideosRealRootPromise = null;
+    localVideosRealRootPromise = fs.realpath(LOCAL_VIDEOS_ROOT)
+      .catch((error) => {
         throw new Error(`Local videos directory is unavailable: ${error.message}`);
+      })
+      .finally(() => {
+        localVideosRealRootPromise = null;
       });
   }