Fix i18n: use initImmediate false for sync initialization

i18n.init() is async by default. With initImmediate: false, it
initializes synchronously so translations are ready before React
hydrates. Without this, useTranslation() runs before i18n is ready,
showing raw translation keys.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

packages/i18n/src/index.ts

@@ -24,6 +24,7 @@ export function initI18n() {
         escapeValue: false,
       },
       showSupportNotice: false,
+      initImmediate: false,
     });
 }