migrate firebase db

src/app/services/fullscreen.ts

@@ -1,13 +1,29 @@
 const elem = document.documentElement;
 
 export const openFullscreen = () => {
-  if (elem.requestFullscreen) {
-    void elem.requestFullscreen();
+  if (!elem.requestFullscreen || !document.fullscreenEnabled) {
+    return;
+  }
+
+  try {
+    const promise = elem.requestFullscreen();
+    if (promise && typeof promise.catch === 'function') {
+      void promise.catch(() => {
+        // Browser may reject when no user gesture is present. Keep app usable.
+      });
+    }
+  } catch {
+    // Some browsers may throw synchronously if fullscreen is not allowed.
   }
 };
 
 export const closeFullscreen = () => {
   if (document.exitFullscreen) {
-    void document.exitFullscreen();
+    const promise = document.exitFullscreen();
+    if (promise && typeof promise.catch === 'function') {
+      void promise.catch(() => {
+        // Ignore; leaving fullscreen is a best-effort action.
+      });
+    }
   }
 };