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/en-US.ts

@@ -593,8 +593,7 @@ const enUS = {
     tabLogs: 'Logs',
     logsLevelAll: 'All levels',
     logsRefresh: 'Refresh',
-    logsAutoRefreshOn: 'Auto-refresh: On',
-    logsAutoRefreshOff: 'Auto-refresh: Off',
+    logsAutoRefresh: 'Auto-refresh',
     logsEmpty:
       'No logs yet. Logs printed by the plugin via logger will appear here.',
     fileUpload: {