删除 NavbarThemeSwitcher 组件，移除不再使用的主题切换功能。

src/layouts/components/NavbarThemeSwitcher.vue

@@ -1,38 +0,0 @@
-<script setup lang="ts">
-import type { ThemeSwitcherTheme } from '@layouts/types'
-import { useI18n } from 'vue-i18n'
-
-const { t } = useI18n()
-
-const themes: ThemeSwitcherTheme[] = [
-  {
-    name: 'auto',
-    title: t('theme.auto'),
-    icon: 'mdi-laptop',
-  },
-  {
-    name: 'light',
-    title: t('theme.light'),
-    icon: 'mdi-weather-sunny',
-  },
-  {
-    name: 'dark',
-    title: t('theme.dark'),
-    icon: 'mdi-weather-night',
-  },
-  {
-    name: 'purple',
-    title: t('theme.purple'),
-    icon: 'mdi-brightness-4',
-  },
-  {
-    name: 'transparent',
-    title: t('theme.transparent'),
-    icon: 'mdi-gradient-horizontal',
-  },
-]
-</script>
-
-<template>
-  <ThemeSwitcher :themes="themes" />
-</template>