接入原生壳外观查询能力

新增 HostBridge appearance.getColorScheme 只读契约和 H5 facade

Expo 壳通过 React Native Appearance 读取系统配色

Tauri 壳通过主窗口 theme 读取桌面配色

补齐外观查询测试、漂移检查和架构文档

apps/mobile-shell/scripts/check-config.mjs

@@ -153,6 +153,7 @@ if (!appSource.includes('capabilities: resolveMobileHostCapabilities()')) {
 
 for (const capability of [
   'host.getRuntime',
+  'appearance.getColorScheme',
   'share.open',
   'share.setTarget',
   'navigation.openNativePage',
@@ -175,3 +176,7 @@ if (!iosMobileCapabilitySet.has('app.setBadgeCount')) {
 if (mobileCapabilitySet.has('app.setBadgeCount')) {
   throw new Error('Android mobile shell base capabilities must not include app.setBadgeCount');
 }
+
+if (!bridgeSource.includes('Appearance.getColorScheme()')) {
+  throw new Error('mobile shell HostBridge must read the native color scheme');
+}