test: 添加完整测试套件（52 个文件，326 个用例）

基于 Vitest 搭建测试基础设施，覆盖后端纯函数、API 路由、
前端 hooks、UI 组件和页面级集成测试。

src/app/api/location/regeo/route.test.ts

@@ -0,0 +1,71 @@
+import { describe, it, expect, vi, beforeEach } from "vitest";
+import { createRequest, parseJsonResponse } from "@/__tests__/helpers/api-test-utils";
+
+vi.mock("@/lib/prisma", () => ({ prisma: {} }));
+
+vi.mock("@/lib/amap", () => ({
+  requireAmapApiKey: vi.fn().mockReturnValue("test-key"),
+}));
+
+const mockFetch = vi.fn();
+vi.stubGlobal("fetch", mockFetch);
+
+import { GET } from "./route";
+
+const mockCtx = { params: Promise.resolve({}) };
+
+beforeEach(() => {
+  vi.clearAllMocks();
+});
+
+describe("GET /api/location/regeo", () => {
+  it("returns reverse geocoded location", async () => {
+    mockFetch.mockResolvedValue({
+      json: () =>
+        Promise.resolve({
+          status: "1",
+          regeocode: {
+            formatted_address: "上海市黄浦区人民大道",
+            addressComponent: {
+              district: "黄浦区",
+              township: "南京东路街道",
+              neighborhood: { name: "人民广场" },
+            },
+          },
+        }),
+    });
+
+    const req = createRequest("/api/location/regeo?lat=31.23&lng=121.47");
+    const res = await GET(req, mockCtx);
+    const { status, data } = await parseJsonResponse(res);
+
+    expect(status).toBe(200);
+    expect(data.name).toContain("黄浦区");
+    expect(data.formatted).toBe("上海市黄浦区人民大道");
+  });
+
+  it("returns null name when API returns no result", async () => {
+    mockFetch.mockResolvedValue({
+      json: () => Promise.resolve({ status: "0" }),
+    });
+
+    const req = createRequest("/api/location/regeo?lat=31.23&lng=121.47");
+    const res = await GET(req, mockCtx);
+    const { data } = await parseJsonResponse(res);
+    expect(data.name).toBeNull();
+  });
+
+  it("returns 400 when coordinates missing", async () => {
+    const req = createRequest("/api/location/regeo");
+    const res = await GET(req, mockCtx);
+    expect(res.status).toBe(400);
+  });
+
+  it("returns 503 when API unavailable", async () => {
+    mockFetch.mockRejectedValue(new Error("network"));
+
+    const req = createRequest("/api/location/regeo?lat=31.23&lng=121.47");
+    const res = await GET(req, mockCtx);
+    expect(res.status).toBe(503);
+  });
+});