fix(web): stop spurious page refresh on account menu open; plugin log auto-refresh as switch

Two unrelated frontend fixes:

- LanguageSelector mounts each time the sidebar account dropdown opens and
  unconditionally called i18n.changeLanguage() on mount, emitting a
  languageChanged event even when the language was unchanged. That handed
  every useTranslation() consumer a fresh `t` reference, re-running effects
  keyed on `t` (e.g. the plugins page system-status fetch) and surfacing as
  a page "refresh". Guard the call so it only fires on an actual change.

- Plugin logs auto-refresh control changed from a toggle Button to a
  Switch + Label; the on/off button i18n keys are replaced by a single
  static logsAutoRefresh label across all 8 locales.

web/src/i18n/locales/zh-Hant.ts

@@ -566,8 +566,7 @@ const zhHant = {
     tabLogs: '日誌',
     logsLevelAll: '全部級別',
     logsRefresh: '重新整理',
-    logsAutoRefreshOn: '自動重新整理：開',
-    logsAutoRefreshOff: '自動重新整理：關',
+    logsAutoRefresh: '自動重新整理',
     logsEmpty: '暫無日誌。外掛透過 logger 列印的日誌會顯示在這裡。',
     fileUpload: {
       tooLarge: '檔案大小超過 10MB 限制',