fix: theme mode follow the system only auto (vbenjs#5923)

* 修复主题在未设置为auto时，仍然会跟随系统主题变化的问题。

Author: mynetfan

packages/@core/preferences/src/preferences.ts

@@ -198,9 +198,16 @@ class PreferenceManager {
     window
       .matchMedia('(prefers-color-scheme: dark)')
       .addEventListener('change', ({ matches: isDark }) => {
-        this.updatePreferences({
-          theme: { mode: isDark ? 'dark' : 'light' },
-        });
+        // 如果偏好设置中主题模式为auto，则跟随系统更新
+        if (this.state.theme.mode === 'auto') {
+          this.updatePreferences({
+            theme: { mode: isDark ? 'dark' : 'light' },
+          });
+          // 恢复为auto模式
+          this.updatePreferences({
+            theme: { mode: 'auto' },
+          });
+        }
       });
   }
 

packages/effects/plugins/src/vxe-table/init.ts

@@ -106,19 +106,19 @@ export function setupVbenVxeTable(setupOptions: SetupVxeTable) {
   initVxeTable();
   useTableForm = useVbenForm;
 
-  const preference = usePreferences();
+  const { isDark, locale } = usePreferences();
 
   const localMap = {
     'zh-CN': zhCN,
     'en-US': enUS,
   };
 
   watch(
-    [() => preference.theme.value, () => preference.locale.value],
-    ([theme, locale]) => {
-      VxeUI.setTheme(theme === 'dark' ? 'dark' : 'light');
-      VxeUI.setI18n(locale, localMap[locale]);
-      VxeUI.setLanguage(locale);
+    [() => isDark.value, () => locale.value],
+    ([isDarkValue, localeValue]) => {
+      VxeUI.setTheme(isDarkValue ? 'dark' : 'light');
+      VxeUI.setI18n(localeValue, localMap[localeValue]);
+      VxeUI.setLanguage(localeValue);
     },
     {
       immediate: true,