[bugfix] fix service worker registration timing to run after Pinia setup (#6272)

Fixes Pinia initialization error that occurred when the auth service
worker tried to access stores before Pinia was set up.

The auth service worker was being imported at the top of `main.ts`,
causing it to register immediately:

```typescript
import '@/platform/auth/serviceWorker'  // Runs immediately on import
```

This happened before Pinia was initialized, causing an error when the
service worker setup tried to use stores:

```
Error: [🍍]: "getActivePinia()" was called but there was no active Pinia.
```

Moved the service worker registration to after Pinia is set up but
before mounting the app:

```typescript
  .use(pinia)
  .use(i18n)
  .use(VueFire, {
    firebaseApp,
    modules: [VueFireAuth()]
  })

// Register auth service worker after Pinia is initialized (cloud-only)
if (isCloud) {
  void import('@/platform/auth/serviceWorker')
}

app.mount('#vue-app')
```

- ✅ Pinia stores are available when service worker setup runs
- ✅ Still tree-shaken for non-cloud builds via dynamic import in `if
(isCloud)`
- ✅ Registers before mounting, so service worker is active from the
start

- Verified no Pinia errors in cloud builds
- Verified tree-shaking still works (service worker code not in
localhost builds)

┆Issue is synchronized with this [Notion
page](https://www.notion.so/PR-6272-bugfix-fix-service-worker-registration-timing-to-run-after-Pinia-setup-2976d73d365081b998dfd2eded782070)
by [Unito](https://www.unito.io)

src/main.ts

@@ -13,7 +13,6 @@ import { VueFire, VueFireAuth } from 'vuefire'
 
 import { FIREBASE_CONFIG } from '@/config/firebase'
 import '@/lib/litegraph/public/css/litegraph.css'
-import '@/platform/auth/serviceWorker'
 import { isCloud } from '@/platform/distribution/types'
 import router from '@/router'
 
@@ -85,4 +84,10 @@ app
     firebaseApp,
     modules: [VueFireAuth()]
   })
-  .mount('#vue-app')
+
+// Register auth service worker after Pinia is initialized (cloud-only)
+if (isCloud) {
+  void import('@/platform/auth/serviceWorker')
+}
+
+app.mount('#vue-app')