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/api.test.ts

@@ -106,6 +106,22 @@ describe("public visitor lookup", () => {
     expect(response.ticket.party_size).toBe(4);
     expect(response.public_token).toBe("visitor-token");
   });
+
+  it("exposes Retry-After for rate-limited ticket requests", async () => {
+    const fetchMock = vi.fn().mockResolvedValue(new Response(JSON.stringify({
+      error: { code: "PUBLIC_TICKET_RATE_LIMITED", message: "取号次数过多，请稍后再试" },
+    }), {
+      status: 429,
+      headers: { "Content-Type": "application/json", "Retry-After": "17" },
+    }));
+    vi.stubGlobal("fetch", fetchMock);
+
+    await expect(api.publicCreateTicket("project-1", { phone: "13800138000", party_size: 1 })).rejects.toMatchObject({
+      code: "PUBLIC_TICKET_RATE_LIMITED",
+      status: 429,
+      retryAfterSeconds: 17,
+    });
+  });
 });
 
 describe("public display overview", () => {