fix(viewer): reveal overlays from fullscreen (#261)

src/client/pages/ViewerPage.tsx

@@ -1534,6 +1534,30 @@ export function ViewerPage({ roomId, viewerGrant }: ViewerPageProps) {
     );
   }, [frameProofEpoch, presentationState.connection, remoteMedia]);
 
+  useEffect(() => {
+    if (presentation.overlay === "none") {
+      return;
+    }
+    const video = videoRef.current as
+      | (HTMLVideoElement & {
+          webkitDisplayingFullscreen?: boolean;
+          webkitExitFullscreen?: () => void;
+        })
+      | null;
+    if (!video) {
+      return;
+    }
+    if (document.fullscreenElement === video) {
+      void document.exitFullscreen().catch(() => undefined);
+      return;
+    }
+    if (video.webkitDisplayingFullscreen) {
+      try {
+        video.webkitExitFullscreen?.();
+      } catch {}
+    }
+  }, [presentation.overlay]);
+
   useEffect(() => {
     dispatchPresentation({
       type: "retry-available",