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/TasksPage.tsx

@@ -60,17 +60,17 @@ export function TasksPage() {
             </thead>
             <tbody>
               {snap.transcodes.map((t) => (
-                <tr key={t.media_id} className="border-t border-white/5">
+                <tr key={t.media_id} className="border-t border-gray-200">
                   <td className="py-2 font-mono text-xs text-ink-600">{t.media_id}</td>
                   <td className="text-ink-100">{t.encoder || 'libx264'}</td>
                   <td className="text-ink-100">{new Date(t.started_at).toLocaleTimeString()}</td>
                   <td>
                     {t.playlist_ok ? (
-                      <span className="rounded border border-emerald-400/40 px-1.5 py-0.5 text-xs text-emerald-400">
+                      <span className="rounded-lg border border-emerald-400/40 px-1.5 py-0.5 text-xs text-emerald-400">
                         ready
                       </span>
                     ) : (
-                      <span className="rounded border border-yellow-400/40 px-1.5 py-0.5 text-xs text-yellow-400">
+                      <span className="rounded-lg border border-yellow-400/40 px-1.5 py-0.5 text-xs text-yellow-400">
                         starting
                       </span>
                     )}
@@ -97,14 +97,14 @@ export function TasksPage() {
             </thead>
             <tbody>
               {torrents.map((t) => (
-                <tr key={t.hash} className="border-t border-white/5 align-top">
+                <tr key={t.hash} className="border-t border-gray-200 align-top">
                   <td className="max-w-md truncate py-2 text-ink-600" title={t.name}>
                     {t.name}
                   </td>
                   <td className="text-ink-100">{t.state}</td>
                   <td className="text-ink-100">
                     <div className="flex items-center gap-2">
-                      <div className="h-1 w-24 overflow-hidden rounded bg-white/10">
+                      <div className="h-1 w-24 overflow-hidden rounded-lg bg-gray-200">
                         <div
                           className="h-full bg-primary-400"
                           style={{ width: `${Math.round(t.progress * 100)}%` }}