TG Bot 命令交互 + UI 圆角色差深度优化 + 通知配置修复

## TG Bot 交互命令系统 (新增)
- telegram_bot.go: 命令路由 + /start /help /status /search /downloads /stats
- telegram_webhook.go: Webhook 接收 + Polling 管理端点
- Polling 模式: 无需公网 HTTPS, 服务器启动自动轮询
- HTML parse_mode 统一消息格式

## 通知配置 BUG 修复
- validateChannel 添加 email 类型支持
- 前后端字段统一: channel_type -> type
- ListByType 新增仓库方法

## UI 深度优化
- glass-panel: 添加 rounded-2xl + 可见边框 + padding
- card: 添加 p-4 sm:p-6
- 全局 rounded-md -> rounded-xl, 裸 rounded -> rounded-lg
- 500+ 深色硬编码类名清零
- text-gray-400 -> gray-500 色差提升
- 按钮组 flex-wrap 防溢出
- data-table 表格溢出截断

web/src/pages/AdminPage.tsx

@@ -17,7 +17,7 @@ export function AdminPage() {
   return (
     <div className="space-y-6">
       <h1 className="font-display text-3xl font-bold text-ink-600">管理后台</h1>
-      <div className="flex flex-wrap gap-2 border-b border-white/10">
+      <div className="flex flex-wrap gap-2 border-b border-gray-200">
         {tabs.map((k) => (
           <button
             key={k.key}
@@ -108,13 +108,13 @@ function LibraryPanel() {
           </thead>
           <tbody>
             {libs.map((l) => (
-              <tr key={l.id} className="border-t border-white/5">
+              <tr key={l.id} className="border-t border-gray-200">
                 <td className="py-2 text-ink-600">{l.name}</td>
                 <td className="text-ink-100">{l.path}</td>
                 <td className="text-ink-100">{l.type}</td>
                 <td className="space-x-2 py-2 text-right">
                   <button
-                    className="rounded border border-primary-400/40 px-2 py-1 text-xs text-brand-500 hover:bg-primary-400/10"
+                    className="rounded-lg border border-primary-400/40 px-2 py-1 text-xs text-brand-500 hover:bg-primary-400/10"
                     onClick={async () => {
                       const r = await libraryAPI.scan(l.id)
                       toast.success(`扫描完成,新增 ${r.added}`)
@@ -123,7 +123,7 @@ function LibraryPanel() {
                     扫描
                   </button>
                   <button
-                    className="rounded border border-red-400/40 px-2 py-1 text-xs text-red-400 hover:bg-red-400/10"
+                    className="rounded-lg border border-red-400/40 px-2 py-1 text-xs text-red-400 hover:bg-red-400/10"
                     onClick={async () => {
                       if (!confirm(`确定删除「${l.name}」?`)) return
                       await libraryAPI.remove(l.id)
@@ -163,7 +163,7 @@ function UsersPanel() {
         </thead>
         <tbody>
           {users.map((u) => (
-            <tr key={u.id} className="border-t border-white/5">
+            <tr key={u.id} className="border-t border-gray-200">
               <td className="py-2 text-ink-600">{u.username}</td>
               <td className="text-ink-100">{u.role}</td>
               <td className="text-ink-50">
@@ -171,7 +171,7 @@ function UsersPanel() {
               </td>
               <td className="py-2 text-right">
                 <button
-                  className="rounded border border-red-400/40 px-2 py-1 text-xs text-red-400 hover:bg-red-400/10"
+                  className="rounded-lg border border-red-400/40 px-2 py-1 text-xs text-red-400 hover:bg-red-400/10"
                   onClick={async () => {
                     if (!confirm(`确定删除「${u.username}」?`)) return
                     await adminAPI.deleteUser(u.id)