refactor(P1): 5 项代码质量改进 — 消除重复、拆分巨型组件、统一基础设施

Task 4: 统一 amap.ts 为完整 API 客户端
- 扩展 amap.ts 为统一客户端（amapFetch 8s 超时 + 错误处理）
- 导出 searchPlaceText/searchPlaceAround/getInputTips/reverseGeocode/getTransitDirection
- 精简 4 个 location route 为单行调用，blindboxPlanGen 删除 ~80 行内联 API 代码

Task 2: 抽取 ShareCardShell 消除三兄弟重复
- 新建 ShareCardShell.tsx 共享外框/背景/品牌头/QR 底部
- RestaurantShareCard 406→268 行，BlindboxShareCard 341→173 行，BlindboxPlanShareCard 277→159 行

Task 3: 拆分 BlindboxPlan.tsx (742→371 行)
- 提取 planUtils.ts (guessCategory + formatDuration)
- 提取 PoiSearchField / SortablePlanItem / PlanItemEditModal 三个独立组件

Task 1: 拆分 blindbox/[code]/page.tsx 上帝组件 (1300→509 行)
- 提取 useBlindboxRoom / useBlindboxIdeas / useBlindboxPlan / useBlindboxDraw 四个 hooks
- 提取 BlindboxPoolPhase / BlindboxRevealPhase 两个子组件
- 主页面仅保留 phase 协调 + hook 组装 + 子组件渲染

Task 5: 统一 SWR 数据获取层
- 新建 fetcher.ts (FetchError 携带 status，401 不重试)
- 新建 useBlindboxRooms / useAchievements / useFavorites SWR hooks
- useRoomPolling 改用共享 fetcher
- blindbox 大厅/成就/个人中心页面删除手写 fetch 样板代码
- JWT 过期时自动弹出登录框而非反复重试

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

@@ -1,6 +1,6 @@
 import { NextResponse } from "next/server";
 import { apiHandler, ApiError } from "@/lib/api";
-import { requireAmapApiKey } from "@/lib/amap";
+import { reverseGeocode } from "@/lib/amap";
 
 export const GET = apiHandler(async (req) => {
   const lat = req.nextUrl.searchParams.get("lat");
@@ -8,37 +8,6 @@ export const GET = apiHandler(async (req) => {
 
   if (!lat || !lng) throw new ApiError("lat and lng are required");
 
-  const apiKey = requireAmapApiKey();
-
-  const url = new URL("https://restapi.amap.com/v3/geocode/regeo");
-  url.searchParams.set("key", apiKey);
-  url.searchParams.set("location", `${lng},${lat}`);
-  url.searchParams.set("extensions", "base");
-
-  let data;
-  try {
-    const res = await fetch(url.toString());
-    data = await res.json();
-  } catch {
-    throw new ApiError("位置服务暂时不可用，请稍后重试", 503);
-  }
-
-  if (data.status !== "1" || !data.regeocode) {
-    return NextResponse.json({ name: null });
-  }
-
-  const comp = data.regeocode.addressComponent;
-  const district = comp?.district || comp?.city || "";
-  const township = comp?.township || "";
-  const neighborhood = comp?.neighborhood?.name || "";
-
-  const name = [district, township, neighborhood]
-    .filter(Boolean)
-    .join(" ")
-    .trim();
-
-  return NextResponse.json({
-    name: name || data.regeocode.formatted_address || null,
-    formatted: data.regeocode.formatted_address || null,
-  });
+  const result = await reverseGeocode({ lat: Number(lat), lng: Number(lng) });
+  return NextResponse.json(result);
 });