fix(i18n): ensure language switch actually re-renders the tree

- `nonExplicitSupportedLngs: true` was normalizing `zh-CN` → `zh` in
  some code paths; since we have explicit `zh-CN` resources, swap it
  for `load: 'currentOnly'` which keeps the code as-is.
- `react: { useSuspense: false }` — react-i18next v17 defaults Suspense
  on, which can silently suspend components mid-switch and look like
  "nothing happens" to the user.
- Use `i18n.language` (the raw current code) instead of
  `resolvedLanguage` in the selector so the dropdown always mirrors
  what we just set.

Co-Authored-By: Claude Opus 4.7 (1M context) <[email protected]>

app/src/components/ServerTab/LanguageSelect.tsx

@@ -10,10 +10,15 @@ import { SUPPORTED_LANGUAGES } from '@/i18n';
 
 export function LanguageSelect() {
   const { i18n } = useTranslation();
-  const current = SUPPORTED_LANGUAGES.find((l) => l.code === i18n.resolvedLanguage)?.code ?? 'en';
+  const current = SUPPORTED_LANGUAGES.find((l) => l.code === i18n.language)?.code ?? 'en';
 
   return (
-    <Select value={current} onValueChange={(value) => i18n.changeLanguage(value)}>
+    <Select
+      value={current}
+      onValueChange={(value) => {
+        void i18n.changeLanguage(value);
+      }}
+    >
       <SelectTrigger className="h-9 w-[180px]">
         <SelectValue />
       </SelectTrigger>