feat(admin): reload once when a chunk fails to load after a deploy (quick-261028-rqb)

- installChunkReloadGuard reloads on vite:preloadError, at most once per
  60 s through a sessionStorage timestamp; no storage means no reload

admin/src/main.ts

@@ -3,6 +3,7 @@ import App from './App.vue'
 import { createAdminRouter } from './app/router'
 import { onUnauthorized } from './api/client'
 import { startBuildWatch } from './app/buildUpdate'
+import { installChunkReloadGuard } from './app/chunkReload'
 import { loadFieldTypes } from './app/fieldTypes'
 import { loadStrings } from './app/i18n'
 import { expireSession, me } from './state/useAuth'
@@ -12,6 +13,8 @@ import { loadSettings } from './state/useSettings'
 import './styles/main.css'
 
 async function boot(): Promise<void> {
+  // A chunk that fails to load after a deploy reloads the page once.
+  installChunkReloadGuard()
   // The last theme choice (system unless the admin picked light or dark) is
   // applied before the first await, so nothing renders in the wrong theme;
   // me() then applies the admin's stored preference.