feat: DevTools 数据库监看面板 + 隧道控制 + 多项 Bug 修复

**DevTools 新增功能 (Tasks 13-14):**
- 首页仪表盘添加数据库实时监看卡片 (5端口状态 + 记忆数)
- 侧边栏新增数据库面板，支持自动 5 秒刷新
- 数据库面板显示 PostgreSQL/Redis/Qdrant/MinIO/NATS 端口状态
- 隧道控制按钮 (启动/停止/重启/查看状态)
- 新增 API 端点: GET /api/database/status, POST /api/tunnel/:action
- 更新 docs/api-reference/ API 文档

**Bug 修复 (Task 15):**
- 修复 pgrep -f 自匹配导致隧道状态误判 (添加 ^ssh 锚点)
  - devtools/src/index.js (dashboard + database/status)
  - scripts/tunnel.sh (is_tunnel_running + show_status)
- 修复数据库面板缺少自动刷新定时器
- 修复侧边栏数据库徽章永远 display:none
- 修复僵尸进程场景下按钮死锁问题

**其他改进:**
- .gitignore 添加 backend/cmd, backend/iot-debug-service/main
- 前端多项改进 (登录/注册/会话/流式动画等)

frontend/web/src/components/chat/ChatContainer.tsx

@@ -1,8 +1,53 @@
 import { useChat } from '@/hooks/useChat';
+import { useChatStore } from '@/store/chatStore';
 import { MessageList } from './MessageList';
+import { IoTStatusBar } from './IoTStatusBar';
 
 export function ChatContainer() {
   const { messages, isTyping } = useChat();
+  const continuousMode = useChatStore((s) => s.continuousMode);
+  const backgroundThinkingStatus = useChatStore((s) => s.backgroundThinkingStatus);
 
-  return <MessageList messages={messages} isTyping={isTyping} />;
+  const thinkingLabel = backgroundThinkingStatus === 'thinking' ? '昔涟正在回忆中...' : '';
+  const statusLabel = continuousMode ? '主对话 · 进行中' : '';
+
+  return (
+    <div className="flex flex-col h-full">
+      {/* 状态指示器栏 */}
+      <div className="flex items-center justify-between px-4 py-1.5 border-b border-pink-100 dark:border-pink-900 bg-pink-50/50 dark:bg-pink-950/20">
+        <div className="flex items-center gap-2">
+          {statusLabel && (
+            <span className="text-xs font-medium text-pink-500 dark:text-pink-400 bg-pink-100 dark:bg-pink-900/50 px-2 py-0.5 rounded-full">
+              {statusLabel}
+            </span>
+          )}
+          {thinkingLabel && (
+            <span className="text-xs text-pink-400 dark:text-pink-500 animate-pulse flex items-center gap-1">
+              <span className="inline-block w-1.5 h-1.5 bg-pink-400 rounded-full animate-bounce" />
+              <span className="inline-block w-1.5 h-1.5 bg-pink-400 rounded-full animate-bounce" style={{ animationDelay: '0.15s' }} />
+              <span className="inline-block w-1.5 h-1.5 bg-pink-400 rounded-full animate-bounce" style={{ animationDelay: '0.3s' }} />
+              {thinkingLabel}
+            </span>
+          )}
+        </div>
+        {continuousMode && (
+          <button
+            onClick={() => useChatStore.getState().setContinuousMode(!continuousMode)}
+            className="text-[10px] text-gray-400 hover:text-gray-600 dark:hover:text-gray-300 transition-colors"
+            title="切换连续对话模式"
+          >
+            {continuousMode ? '🔗 连续对话' : '⏸️ 暂停中'}
+          </button>
+        )}
+      </div>
+
+      {/* 消息列表 */}
+      <div className="flex-1 overflow-hidden">
+        <MessageList messages={messages} isTyping={isTyping} />
+      </div>
+
+      {/* IoT 状态栏（底部） */}
+      <IoTStatusBar />
+    </div>
+  );
 }