fix: 修复远端公告不刷新与盔甲面板未翻译

Bug1 远端公告：公告只在启动时拉取一次，且点铃铛不触发刷新。
- openCenter 时补调 refresh()，点铃铛即拉最新
- watch skinSiteStatus，登录皮肤站后自动重试拉取

Bug2 盔甲翻译：补 7 个缺失的 app.skins.armor.* i18n 键
（title/save/close/description/unsaved/reset-to-saved/restore-defaults），
ui 包的 skin.preview.armor.* 46 个键已存在无需补。

apps/app-frontend/src/locales/en-US/index.json

@@ -11554,5 +11554,12 @@
   },
   "app.settings.logs.export.notification-text": {
     "message": "The log archive was saved to {path}"
-  }
-}
+  },
+  "app.skins.armor.title": {"message": "Armour and trims"},
+  "app.skins.armor.save": {"message": "Save"},
+  "app.skins.armor.close": {"message": "Close"},
+  "app.skins.armor.description": {"message": "Try armour and trims on your skin. Nothing is stored until you save it."},
+  "app.skins.armor.unsaved": {"message": "Unsaved changes"},
+  "app.skins.armor.reset-to-saved": {"message": "Reset to saved"},
+  "app.skins.armor.restore-defaults": {"message": "Restore defaults"}
+}