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/achievements/page.tsx

@@ -19,17 +19,11 @@ import ContractHistoryItem from "@/components/ContractHistoryItem";
 import EmptyState from "@/components/EmptyState";
 import { Skeleton, RecordItemSkeleton } from "@/components/Skeleton";
 import { buildNavUrl } from "@/lib/navigation";
-import type { DecisionRecord, ContractRecord, Restaurant } from "@/types";
+import { useAchievements } from "@/hooks/useAchievements";
+import type { Restaurant } from "@/types";
 
 type Tab = "decisions" | "contracts";
 
-interface Stats {
-  totalDecisions: number;
-  totalContracts: number;
-  completedContracts: number;
-  completionRate: number;
-}
-
 function firstImage(r: Restaurant): string {
   if (r.images?.length > 0) return r.images[0];
   const legacy = (r as unknown as Record<string, unknown>).image;
@@ -38,16 +32,8 @@ function firstImage(r: Restaurant): string {
 
 export default function AchievementsPage() {
   const router = useRouter();
-  const [loading, setLoading] = useState(true);
   const [tab, setTab] = useState<Tab>("decisions");
-  const [stats, setStats] = useState<Stats>({
-    totalDecisions: 0,
-    totalContracts: 0,
-    completedContracts: 0,
-    completionRate: 0,
-  });
-  const [decisions, setDecisions] = useState<DecisionRecord[]>([]);
-  const [contracts, setContracts] = useState<ContractRecord[]>([]);
+  const [userId, setUserId] = useState<string | undefined>(undefined);
 
   useEffect(() => {
     if (!isRegistered()) {
@@ -55,21 +41,11 @@ export default function AchievementsPage() {
       return;
     }
     const p = getCachedProfile();
-    if (!p) return;
-
-    (async () => {
-      try {
-        const res = await fetch(`/api/user/achievements?userId=${p.id}`);
-        if (!res.ok) return;
-        const data = await res.json();
-        setStats(data.stats);
-        setDecisions(data.decisions);
-        setContracts(data.contracts);
-      } catch (e) { console.error("AchievementsPage: fetch failed:", e); }
-      finally { setLoading(false); }
-    })();
+    if (p) setUserId(p.id);
   }, [router]);
 
+  const { stats, decisions, contracts, isLoading: loading } = useAchievements(userId);
+
   const statCards = [
     {
       label: "决策记录",