feat: Iteration 3 — 咨询轮询、统计概览、埋点后端

- consultation_service 支持 after_id 增量消息查询
- 小程序咨询详情页 8 秒轮询新消息
- 新增 DashboardStatsResp 综合统计端点 (/statistics/dashboard)
- 新增 /analytics/batch 埋点接收端点（日志记录模式）

apps/miniprogram/src/pages/doctor/consultation/detail/index.tsx

@@ -5,6 +5,8 @@ import * as doctorApi from '@/services/doctor';
 import Loading from '@/components/Loading';
 import './index.scss';
 
+const POLL_INTERVAL = 8000;
+
 export default function ConsultationDetail() {
   const router = useRouter();
   const sessionId = router.params.id || '';
@@ -14,14 +16,53 @@ export default function ConsultationDetail() {
   const [sending, setSending] = useState(false);
   const [loading, setLoading] = useState(true);
   const scrollViewRef = useRef('');
+  const pollTimerRef = useRef<ReturnType<typeof setInterval> | null>(null);
 
   useEffect(() => {
     if (sessionId) {
       loadData();
       markRead();
+      startPolling();
     }
+    return () => stopPolling();
   }, [sessionId]);
 
+  const startPolling = () => {
+    stopPolling();
+    pollTimerRef.current = setInterval(pollNewMessages, POLL_INTERVAL);
+  };
+
+  const stopPolling = () => {
+    if (pollTimerRef.current) {
+      clearInterval(pollTimerRef.current);
+      pollTimerRef.current = null;
+    }
+  };
+
+  const pollNewMessages = async () => {
+    if (!session || session.status === 'closed') {
+      stopPolling();
+      return;
+    }
+    try {
+      const lastId = messages.length > 0 ? messages[messages.length - 1].id : undefined;
+      const m = await doctorApi.listMessages(sessionId, {
+        page: 1,
+        page_size: 50,
+        after_id: lastId,
+      });
+      const newMsgs = m.data || [];
+      if (newMsgs.length > 0) {
+        setMessages((prev) => {
+          const existing = new Set(prev.map((msg) => msg.id));
+          const fresh = newMsgs.filter((msg) => !existing.has(msg.id));
+          return [...prev, ...fresh];
+        });
+        scrollViewRef.current = `msg-${messages.length + newMsgs.length}`;
+      }
+    } catch { /* 轮询失败静默忽略 */ }
+  };
+
   const loadData = async () => {
     setLoading(true);
     try {
@@ -32,6 +73,7 @@ export default function ConsultationDetail() {
       setSession(s);
       setMessages(m.data || []);
       scrollViewRef.current = `msg-${(m.data || []).length}`;
+      if (s.status === 'closed') stopPolling();
     } catch {
       Taro.showToast({ title: '加载失败', icon: 'none' });
     } finally {