Add auth servers unreachable warning to app (#4774)

* Add auth servers unreachable warning to app

* Check auth status every 5 minutes

* Use admonition in auth server warning

* feat: tanstack

* Fix auth server reachability query

* Format

* intl extract

---------

Co-authored-by: Calum H. (IMB11) <contact@cal.engineer>

apps/app-frontend/src/helpers/auth.js

@@ -13,6 +13,14 @@ import { invoke } from '@tauri-apps/api/core'
 //   await authenticate_await_completion()
 // }
 
+/**
+ * Check if the authentication servers are reachable, throwing an exception if
+ * not reachable.
+ */
+export async function check_reachable() {
+	await invoke('plugin:auth|check_reachable')
+}
+
 /**
  * Authenticate a user with Hydra - part 1.
  * This begins the authentication flow quasi-synchronously.