重构项目，方便开发

frontend-vue/src/components/layout/PageShell.vue

@@ -0,0 +1,20 @@
+<template>
+  <div class="page-shell" :class="themeClass">
+    <slot />
+  </div>
+</template>
+
+<script setup lang="ts">
+import { computed } from 'vue'
+
+const props = withDefaults(
+  defineProps<{
+    theme?: 'light' | 'dark'
+  }>(),
+  {
+    theme: 'light',
+  },
+)
+
+const themeClass = computed(() => `theme-${props.theme}`)
+</script>