feat(ui): 优化 Header 和状态栏布局

- ContextUsage: 紧凑模式下始终显示压缩按钮
- StatusBar: 连接状态移至中间位置，显示绿点动画和文字
- StatusBar: 添加内部连接状态检测（通过 health API）
- Chat: 移除 Header 中的连接状态指示器

packages/web/src/pages/Chat.tsx

@@ -3,7 +3,7 @@
  */
 
 import { useEffect, useRef } from 'react';
-import { WifiOff, MessageSquare, Terminal, Plug, Zap, Bot, History, Server, MessagesSquare } from 'lucide-react';
+import { MessageSquare, Terminal, Plug, Zap, Bot, History, Server, MessagesSquare } from 'lucide-react';
 import { motion, AnimatePresence } from 'framer-motion';
 import { toast } from 'sonner';
 import {
@@ -129,30 +129,6 @@ export function ChatPage({
     </motion.div>
   );
 
-  // 连接状态指示器
-  const ConnectionStatus = () => (
-    <div className="flex items-center gap-1.5 text-sm">
-      {isConnected ? (
-        <motion.div
-          initial={{ opacity: 0 }}
-          animate={{ opacity: 1 }}
-          className="flex items-center gap-1.5"
-        >
-          <span className="relative flex h-2.5 w-2.5">
-            <span className="animate-ping absolute inline-flex h-full w-full rounded-full bg-green-400 opacity-75" />
-            <span className="relative inline-flex rounded-full h-2.5 w-2.5 bg-green-500" />
-          </span>
-          <span className="text-green-400 hidden sm:inline">Connected</span>
-        </motion.div>
-      ) : (
-        <div className="flex items-center gap-1.5 text-red-400">
-          <WifiOff size={16} />
-          <span className="hidden sm:inline">Disconnected</span>
-        </div>
-      )}
-    </div>
-  );
-
   return (
     <div className="flex-1 flex flex-col h-full">
       {/* Header */}
@@ -164,14 +140,11 @@ export function ChatPage({
             <ContextUsage
               sessionId={sessionId}
               compact
-              showCompressButton={false}
+              showCompressButton
               refreshInterval={30000}
             />
           )}
 
-          {/* 连接状态 */}
-          <ConnectionStatus />
-
           {/* 工具栏按钮 */}
           {(onOpenCommands || onOpenMCP || onOpenHooks || onOpenAgents || onOpenCheckpoints || onOpenProviders || onOpenLSP || onOpenDiagnostics || onOpenSessions) && (
             <div className="flex items-center gap-1.5 border-l border-line-muted pl-3">