feat(admin-ui): 管理后台整体切换为浅色主题(ModernLight) + 新增 lightbulb 图标

1. layout(管理控制台 dashboard.vue): main bg-[#09090b] text-zinc-100 → bg-[#f8fafc] text-zinc-900; header bg-zinc-950/60 border-zinc-800 → bg-white/80 border-zinc-200; 移动菜单按钮/新手引导按钮 text-zinc-300/400 hover:bg-zinc-800 → text-zinc-600 hover:bg-zinc-100 border-zinc-200

2. Admin/Sidebar.vue: bg-[#09090b] border-zinc-800 → bg-white border-zinc-200 + shadow-sm; 标题 text-zinc-100 → 900; activeTab bg-blue-600/10 text-blue-400 → bg-blue-50 text-blue-700 border-blue-200; 未选中 text-zinc-500 hover:text-zinc-200 hover:bg-zinc-800/40 → text-zinc-600 hover:text-zinc-900 hover:bg-zinc-100; 用户卡 avatar/首字母 bg-white/70 border-zinc-200 + 退出按钮 hover:bg-red-50 text-red-600

3. 批量 33 个 Admin 组件硬编码深色原子类 1414 处替换(bg-zinc-9xx / border-zinc-8xx / text-zinc-100,200,300 / shadow-black/ -> 对应 light 版本) + style 块原生 CSS rgba(255,255,255,x) 16 处改为 rgba(0,0,0,x) / var 浅色主题 + 硬编码 bg-[#0c0c0e] / border-white/10 / color:white / surface-primary fallback 对应浅色修正

4. 二轮批量追加: bg-zinc-950 + opacity 变体(80/60/50/40/30/20/10) 共 431 处 → bg-white 对应 opacity 版本；placeholder:text-zinc-800 → 500；text-blue/red/emerald/amber/rose/purple 400 版 → 700/600 深浅一致版；border color /500 /30 → 200；focus:ring /20 → /30；shadow color 阴影降低强度

5. hover:text-white 扫尾: 13 处 DataAnalysisPanel/DatabaseManager/NotificationSender/SemesterManager/SongManagement/UserSongsModal hover 文本从 white → zinc-900；按钮三态从 hover:bg-*600 白字 → hover:bg-*-100/200 对应深字色，和前台 indigo/浅色体系保持一致

6. BlacklistManager 前台可见提示 💡→ <Icon lightbulb amber-600 size=13>；ChangelogManager 徽章色从 emerald-300/blue-300/zinc-400 → emerald-700/blue-700/zinc-600 可读；Icon.vue 新增 lightbulb 分支 stroke 图标

7. 受影响文件: dashboard.vue + Sidebar.vue + Icon.vue + Admin/* (33个组件共 1874 处批量替换 + 20 处手工精细化修正)

app/components/Admin/ScheduleForm.vue

@@ -1,18 +1,18 @@
 <template>
   <div
-    class="backdrop-blur-md p-6 rounded-xl border border-white/10 bg-slate-800/70 shadow-2xl max-w-[400px] mx-auto text-zinc-100 transition-transform duration-200 hover:-translate-y-0.5 hover:shadow-[0_15px_30px_rgba(0,0,0,0.2)]"
+    class="backdrop-blur-md p-6 rounded-xl border border-zinc-200 bg-slate-800/70 shadow-2xl max-w-[400px] mx-auto text-zinc-900 transition-transform duration-200 hover:-translate-y-0.5 hover:shadow-[0_15px_30px_rgba(0,0,0,0.2)]"
   >
-    <h3 class="mb-6 pb-2 border-b border-white/10 text-zinc-100 font-bold text-lg">
+    <h3 class="mb-6 pb-2 border-b border-zinc-200 text-zinc-900 font-bold text-lg">
       为歌曲 "{{ song?.title }}" 创建排期
     </h3>
 
     <form @submit.prevent="handleSubmit">
       <div class="mb-4">
-        <label class="block mb-2 font-medium text-zinc-100" for="playDate">播放日期</label>
+        <label class="block mb-2 font-medium text-zinc-900" for="playDate">播放日期</label>
         <input
           id="playDate"
           v-model="playDate"
-          class="w-full p-3 border border-white/10 rounded-lg text-base bg-[#0f172a99] text-zinc-100 outline-none transition-colors duration-150 focus:border-indigo-500 focus:shadow-[0_0_0_2px_rgba(99,102,241,0.25)]"
+          class="w-full p-3 border border-zinc-200 rounded-lg text-base bg-white/90 text-zinc-900 outline-none transition-colors duration-150 focus:border-indigo-500 focus:shadow-[0_0_0_2px_rgba(99,102,241,0.25)]"
           required
           type="date"
         >
@@ -51,7 +51,7 @@
 
       <div class="flex justify-between gap-4 mt-6">
         <button
-          class="flex-1 p-3 border border-white/10 rounded-lg text-base cursor-pointer transition-all duration-200 bg-white/10 text-zinc-100 hover:bg-white/15"
+          class="flex-1 p-3 border border-zinc-200 rounded-lg text-base cursor-pointer transition-all duration-200 bg-white/10 text-zinc-900 hover:bg-white/15"
           type="button"
           @click="$emit('cancel')"
         >