修复：调整游客取号限流策略

问题：移动网络共享出口 IP 会造成游客取号被误限流。

实现：移除公开取号 IP 限制，改用项目总量与手机号 HMAC 限流，并支持 Retry-After 倒计时。

web/src/pages/VisitorTakeTicketPage.tsx

@@ -27,7 +27,7 @@ function keyForIntent(ref: { current: WriteIntent | null }, fingerprint: string)
 }
 
 function releaseIntentAfterDefinitiveError(ref: { current: WriteIntent | null }, error: unknown) {
-  if (error instanceof ApiError && error.status >= 400 && error.status < 500) ref.current = null;
+  if (error instanceof ApiError && error.status >= 400 && error.status < 500 && error.status !== 429) ref.current = null;
 }
 
 function ticketStatusPath(response: CreateTicketResponse): string | null {
@@ -49,8 +49,17 @@ export function VisitorTakeTicketForm() {
   const [confirmDuplicatePhone, setConfirmDuplicatePhone] = useState(false);
   const [createdTicket, setCreatedTicket] = useState<CreateTicketResponse | null>(null);
   const [busy, setBusy] = useState(false);
+  const [retryAfterSeconds, setRetryAfterSeconds] = useState(0);
   const createIntentRef = useRef<WriteIntent | null>(null);
 
+  useEffect(() => {
+    if (retryAfterSeconds <= 0) return;
+    const timer = window.setTimeout(() => {
+      setRetryAfterSeconds((current) => Math.max(0, current - 1));
+    }, 1000);
+    return () => window.clearTimeout(timer);
+  }, [retryAfterSeconds]);
+
   useEffect(() => {
     if (!projects.length) return;
     if (!projects.some((project) => project.id === selectedProjectId)) {
@@ -91,6 +100,7 @@ export function VisitorTakeTicketForm() {
 
   async function submitTicket(event: FormEvent<HTMLFormElement>) {
     event.preventDefault();
+    if (retryAfterSeconds > 0) return;
     if (!selectedProjectId) {
       setFormError("请选择要排队的项目");
       return;
@@ -118,14 +128,21 @@ export function VisitorTakeTicketForm() {
       setCreatedTicket(response);
       setTicketForm({ ...initialTicket, party_size: minPartySize });
       setConfirmDuplicatePhone(false);
+      setRetryAfterSeconds(0);
     } catch (caught) {
       if (caught instanceof ApiError && caught.code === "DUPLICATE_PHONE") {
         createIntentRef.current = null;
         setConfirmDuplicatePhone(true);
         setFormError(null);
+        setRetryAfterSeconds(0);
+      } else if (caught instanceof ApiError && caught.status === 429) {
+        setConfirmDuplicatePhone(false);
+        setFormError(null);
+        setRetryAfterSeconds(caught.retryAfterSeconds ?? 60);
       } else {
         releaseIntentAfterDefinitiveError(createIntentRef, caught);
         setConfirmDuplicatePhone(false);
+        setRetryAfterSeconds(0);
         setFormError(caught instanceof ApiError ? caught.message : "取号未提交，请检查当前数据后重试。");
       }
     } finally {
@@ -247,9 +264,10 @@ export function VisitorTakeTicketForm() {
             </fieldset>
           </div>
           {confirmDuplicatePhone ? <FeedbackBanner tone="warning" title="该手机号已有活动号码">如需继续取号，请再次点击确认按钮。</FeedbackBanner> : null}
+          {retryAfterSeconds > 0 ? <FeedbackBanner tone="warning" title={`请求过于频繁，请在 ${retryAfterSeconds} 秒后重试。`} /> : null}
           {formError ? <FeedbackBanner tone="danger" title={formError} /> : null}
-          <button className="button button--primary button--wide" type="submit" disabled={busy || !selectedProjectId || !projects.length}>
-            {busy ? "正在创建排队号码" : confirmDuplicatePhone ? "确认继续取号" : "创建排队号码"}
+          <button className="button button--primary button--wide" type="submit" disabled={busy || retryAfterSeconds > 0 || !selectedProjectId || !projects.length}>
+            {busy ? "正在创建排队号码" : retryAfterSeconds > 0 ? `请等待 ${retryAfterSeconds} 秒` : confirmDuplicatePhone ? "确认继续取号" : "创建排队号码"}
           </button>
         </form>
       )}