Refactor layout components to improve responsiveness and accessibility; integrate appShell classes for consistent styling across DesktopAIShell and BottomNav. Update SelectPage to enhance option selection UI with image support and language filtering logic in SystemPage for better localization handling.

client/src/pages/SystemPage.tsx

@@ -107,6 +107,18 @@ function optionLabels(items: Array<{ index: number; label: string }> | undefined
   return sorted.map((item) => item.label);
 }
 
+/** Device language index: 0=en, 1=zh-HK, 2=zh-CN */
+const SUPPORTED_LANGUAGE_INDICES = new Set([0, 1, 2]);
+
+function languageLabels(
+  items: Array<{ index: number; label: string }> | undefined,
+  fallback: string[],
+) {
+  const filtered = (items ?? []).filter((o) => SUPPORTED_LANGUAGE_INDICES.has(o.index));
+  if (filtered.length === 0) return fallback;
+  return [...filtered].sort((a, b) => a.index - b.index).map((o) => o.label);
+}
+
 export default function SystemPage() {
   const [, setLocation] = useLocation();
   const { deviceState, updateSetting, refresh, isConnected, api, ip } = useDevice();
@@ -124,7 +136,8 @@ export default function SystemPage() {
   const screenOffIdx = ds?.screenOff ?? 2;
   const sleepIdx = ds?.sleep ?? 0;
   const autoHomeIdx = ds?.autoHome ?? 1;
-  const langIdx = ds?.language ?? 2;
+  const rawLangIdx = ds?.language ?? 2;
+  const langIdx = SUPPORTED_LANGUAGE_INDICES.has(rawLangIdx) ? rawLangIdx : 2;
   const knobBreathLightOn = (ds?.knob_breathlight ?? 1) === 0;
   const localeData = LOCALE_BY_LANG[langIdx] ?? localeZh;
   const settingsText = localeData.settings;
@@ -134,7 +147,11 @@ export default function SystemPage() {
   const SCREEN_OFF_OPTIONS = optionLabels(settingsText.turnOffScreen?.options, ["常亮", "30秒", "1分钟", "3分钟", "5分钟"]);
   const SLEEP_OPTIONS = optionLabels(settingsText.sleepTime?.options ?? settingsText.sleep?.options, ["关闭", "1分钟", "5分钟", "10分钟"]);
   const AUTO_HOME_OPTIONS = optionLabels(settingsText.Automatic?.options, ["关闭", "20秒", "40秒", "60秒"]);
-  const LANG_OPTIONS = optionLabels(settingsText.language?.options, ["English", "繁體中文", "简体中文"]);
+  const LANG_OPTIONS = languageLabels(settingsText.language?.options, [
+    "English",
+    "繁體中文",
+    "简体中文",
+  ]);
 
   const sleepRowLabel =
     settingsText.sleepTime?.label ??