feat(v1.2): 体验升级 — 快捷键系统 + 标签拖拽 + SFTP拖拽上传 + 组件拆分 + 响应式

任务1: 全局快捷键管理器 — useKeyboardShortcuts hook
  Ctrl+Tab/Shift+Tab标签切换, Ctrl+1~9跳转, F11全屏, Ctrl+Shift+N新建标签

任务2: 标签拖拽排序 — tabStore.moveTab + TabBar HTML5 DnD
  不可变更新, 拖拽视觉反馈(opacity+指示线), 活跃标签底部accent-blue指示线

任务3: SFTP拖拽上传 + useSFTP调试清理
  FileListPanel拖拽覆盖层(Upload图标+虚线边框), 5个调试函数→createLogger,
  disconnect()正确调用IPC, 删除mock data

任务4: SFTP右键菜单完善 — 重命名/复制路径/属性/权限
  FilePropertiesDialog+ChmodDialog, sftpStat/sftpChmod IPC全栈实现

任务5-6: 侧边栏分组折叠动画 + 宽度可拖拽调整
  Grid 0fr→1fr折叠动画, ChevronRight旋转, resize handle 180~400px, settings记忆

任务7: 响应式布局 + 视觉优化V1~V5
  useMediaQuery hook, <800px侧边栏overlay模式, SFTP垂直堆叠, WelcomeView响应式grid

任务8: Loading/Skeleton骨架屏
  Skeleton/SkeletonLine/SkeletonCircle/SkeletonBlock + FileListSkeleton/SessionTreeSkeleton/TabContentSkeleton

任务9: 空状态设计
  EmptyState通用组件, SessionTree/FileListPanel/WelcomeView/SFTPView空状态引导

任务10: TerminalView组件拆分重构 711行→285行
  useTerminalConnection(300行) + useTerminalSearch(123行)
  + TerminalOverlay(98行) + TerminalSearchBar(74行)

33 files changed, 2682 insertions(+), 872 deletions(-)

src/components/WelcomeView.tsx

@@ -1,6 +1,7 @@
-import { Terminal, FolderSync, ArrowRightLeft, Globe, Settings, Plus, Zap, Inbox } from 'lucide-react'
+import { Terminal, FolderSync, ArrowRightLeft, Globe, Settings, Plus, Zap, Clock } from 'lucide-react'
 import { useSessionStore } from '../stores'
 import { useTabStore } from '../stores/tabStore'
+import EmptyState from './common/EmptyState'
 
 interface WelcomeViewProps {
   onNewSession?: () => void
@@ -30,7 +31,7 @@ export default function WelcomeView({ onNewSession, onQuickConnect }: WelcomeVie
         </div>
       </div>
 
-      <div className="grid grid-cols-2 gap-4 w-full max-w-2xl mb-12">
+      <div className="grid grid-cols-1 sm:grid-cols-2 gap-4 w-full max-w-2xl mb-12">
         <button
           onClick={onQuickConnect}
           className="flex items-center gap-4 p-6 bg-dark-800 hover:bg-dark-700 rounded-xl border border-dark-700 hover:border-accent-blue transition-all group"
@@ -101,11 +102,11 @@ export default function WelcomeView({ onNewSession, onQuickConnect }: WelcomeVie
       <div className="w-full max-w-2xl">
         <h3 className="text-sm font-medium text-gray-400 mb-4">最近连接</h3>
         {recentSessions.length === 0 ? (
-          <div className="flex flex-col items-center justify-center py-10 text-gray-500">
-            <Inbox className="w-10 h-10 mb-3 text-gray-600" />
-            <p className="text-sm">暂无会话记录</p>
-            <p className="text-xs mt-1">点击上方「新建会话」创建第一个连接</p>
-          </div>
+          <EmptyState
+            icon={Clock}
+            title="暂无最近连接"
+            description="开始你的第一次连接吧"
+          />
         ) : (
           <div className="space-y-2">
             {recentSessions.map((session) => (