Ad view: reliable exit on mobile/dApp browsers

window.close() is blocked in mobile and in-app wallet (dApp) browsers, which left
users stuck on the ad-view tab. Made "Back to dashboard" the primary action, and
"Close tab" now falls back to navigating to /my#earn when the browser refuses to
close the tab.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

public/assets/view.js

@@ -82,7 +82,12 @@
   }
   $('vClose').addEventListener('click', () => {
     window.close();
-    setMsg('You can close this tab now.');
+    // window.close() is blocked in mobile and in-app (wallet dApp) browsers. If
+    // the tab is still here a moment later, take them back to the dashboard so
+    // they are never stuck on a tab they can't close.
+    setTimeout(() => {
+      if (!window.closed) { setMsg('Taking you back to your dashboard…'); location.href = '/my#earn'; }
+    }, 400);
   });
   (async () => {
     const info = await j('/api/my/viewinfo?token=' + token);