fix: move cabinet_branding to sessionStorage and add WebGL availability check

- Branding cache moved from localStorage to sessionStorage so it clears
  when the mini-app is closed, preventing stale names after admin updates
- Added initialDataUpdatedAt: 0 to all branding queries so fresh data is
  always fetched on page refresh while showing cached data instantly
- One-time migration moves existing localStorage value to sessionStorage
- Aurora component now checks WebGL availability upfront, skipping all
  hooks and subscriptions when WebGL is not supported

src/pages/Login.tsx

@@ -90,6 +90,7 @@ export default function Login() {
     },
     staleTime: 60000,
     initialData: cachedBranding ?? undefined,
+    initialDataUpdatedAt: 0,
   });
 
   // Check if email auth is enabled