fix: update themeVars access in useTheme composable and theme settings page

src/composables/useTheme.ts

@@ -36,7 +36,7 @@ export function useTheme() {
     theme: computed(() => store.theme),
     isDark: computed(() => store.isDark),
     currentThemeColor: computed(() => store.currentThemeColor),
-    themeVars: computed(() => store.themeVars),
+    themeVars: store.themeVars,
 
     themeColorOptions,
 

src/pages/mine/settings/theme/index.vue

@@ -147,7 +147,7 @@ const showCustomColorInput = ref(false);
 
 // 当前选中的主题色
 const currentThemeColor = computed(() => {
-  return themeVars.value.colorTheme || themeColorOptions[0].primary;
+  return themeVars.colorTheme || themeColorOptions[0].primary;
 });
 
 // 选择预设颜色