feat(wrapped-ui): 引入多主题系统与切换器（Modern/Game Boy/DOS/VHS）

- 新增 useWrappedTheme：主题状态全局共享、localStorage 持久化，支持 F1-F4 快捷键与循环切换

- 新增主题切换器组件（Modern/Game Boy/DOS/VHS）与主题化年份选择器

- 年度总结页接入 themeClass/currentBg；CRT 叠加层支持 VHS 效果（REC/时间戳/跟踪线）

- 补充主题全局样式与卡片/控制面板主题适配

frontend/components/wrapped/shared/WrappedThemeSwitcherDos.vue

@@ -0,0 +1,100 @@
+<template>
+  <div class="dos-menu select-none">
+    <!-- DOS 风格功能键菜单栏 -->
+    <div class="dos-menu-bar">
+      <button
+        v-for="(t, idx) in themes"
+        :key="t.value"
+        class="dos-menu-item"
+        :class="{ 'is-active': theme === t.value }"
+        @click="setTheme(t.value)"
+      >
+        <span class="dos-fkey">F{{ idx + 1 }}</span>
+        <span class="dos-label">{{ t.label }}</span>
+      </button>
+    </div>
+    <!-- 状态提示 -->
+    <div class="dos-status">
+      Press F1-F4 to switch theme
+    </div>
+  </div>
+</template>
+
+<script setup>
+const { theme, setTheme } = useWrappedTheme()
+
+const themes = [
+  { value: 'off', label: 'Modern' },
+  { value: 'gameboy', label: 'GameBoy' },
+  { value: 'dos', label: 'DOS' },
+  { value: 'vhs', label: 'VHS' }
+]
+</script>
+
+<style scoped>
+.dos-menu {
+  font-family: 'Courier New', 'Consolas', monospace;
+  font-size: 11px;
+}
+
+.dos-menu-bar {
+  display: flex;
+  background: #000000;
+  border: 1px solid #33ff33;
+  overflow: hidden;
+}
+
+.dos-menu-item {
+  display: flex;
+  align-items: center;
+  gap: 2px;
+  padding: 4px 8px;
+  background: #000000;
+  color: #33ff33;
+  border: none;
+  border-right: 1px solid #1a5c1a;
+  cursor: pointer;
+  text-shadow: 0 0 5px #33ff33;
+  transition: all 0.1s;
+  font-family: inherit;
+  font-size: inherit;
+}
+
+.dos-menu-item:last-child {
+  border-right: none;
+}
+
+.dos-menu-item:hover {
+  background: #0a1a0a;
+}
+
+.dos-menu-item.is-active {
+  background: #33ff33;
+  color: #000000;
+  text-shadow: none;
+}
+
+.dos-fkey {
+  font-weight: bold;
+  padding: 1px 3px;
+  background: #1a5c1a;
+  color: #33ff33;
+  font-size: 9px;
+}
+
+.dos-menu-item.is-active .dos-fkey {
+  background: #000000;
+  color: #33ff33;
+}
+
+.dos-label {
+  letter-spacing: 0.5px;
+}
+
+.dos-status {
+  margin-top: 4px;
+  color: #1a5c1a;
+  font-size: 9px;
+  text-shadow: 0 0 3px #1a5c1a;
+}
+</style>