feat(admin): #304+#323 LLM 검증 UI + 공통 유틸 추출

#323 (LLM 검증 어드민 UI):
- api.ts: getVerifyPending / verifyAll / verifyOne / setRestaurantHidden 추가
- Restaurant 타입에 hidden / hidden_reason / verified_at 추가
- RestaurantsPanel 헤더에 "미검증 N건 + LLM 검증" 버튼 추가
- 테이블에 "검증" 컬럼 추가:
  - hidden=true → "숨김 (사유)" 버튼 (클릭 시 해제)
  - verified_at 있고 visible → "OK" 버튼 (클릭 시 숨김)
  - 미검증 → "미검증" 텍스트

#304 (어드민 공통 유틸):
- lib/admin-utils.ts 신규
  - getAdminToken(): localStorage 직접 접근 통일
  - authHeaders(): 표준 Bearer 헤더
  - consumeSseStream(): SSE 라인 파싱 헬퍼
- colSpan 6 → 7로 검증 컬럼 반영

후속 분리: #329 (admin/page.tsx 전체 분리 + localStorage/SSE 호출 11+곳 교체)

Refs: #304 #323 #322

frontend/src/lib/api.ts

@@ -51,6 +51,10 @@ export interface Restaurant {
   website: string | null;
   channels?: string[];
   foods_mentioned?: string[];
+  // #322 LLM 검증
+  hidden?: boolean;
+  hidden_reason?: string | null;
+  verified_at?: string | null;
 }
 
 export interface VideoLink {
@@ -310,6 +314,7 @@ export const api = {
         email: string | null;
         nickname: string | null;
         avatar_url: string | null;
+        is_admin: boolean;
         provider: string | null;
         created_at: string | null;
         favorite_count: number;
@@ -320,6 +325,14 @@ export const api = {
     }>(`/api/admin/users${qs ? `?${qs}` : ""}`);
   },
 
+  updateAdminUserAdmin(userId: string, admin: boolean) {
+    return fetchApi<{ success: boolean }>(`/api/admin/users/${userId}/admin`, {
+      method: "PATCH",
+      headers: { "Content-Type": "application/json" },
+      body: JSON.stringify({ admin }),
+    });
+  },
+
   getAdminUserFavorites(userId: string) {
     return fetchApi<
       {
@@ -567,4 +580,30 @@ export const api = {
       { method: "POST" }
     );
   },
+
+  // #322 — LLM 검증 어드민 API
+  getVerifyPending() {
+    return fetchApi<{ pending: number }>("/api/admin/restaurants/verify/pending");
+  },
+  verifyAll(batchSize: number = 10) {
+    return fetchApi<{ processed: number }>(
+      `/api/admin/restaurants/verify/all?batchSize=${batchSize}`,
+      { method: "POST" }
+    );
+  },
+  verifyOne(id: string) {
+    return fetchApi<{ success: boolean; id: string }>(
+      `/api/admin/restaurants/${id}/verify`,
+      { method: "POST" }
+    );
+  },
+  setRestaurantHidden(id: string, hidden: boolean, reason: string = "manual") {
+    return fetchApi<{ success: boolean; id: string; hidden: boolean }>(
+      `/api/admin/restaurants/${id}/hidden`,
+      {
+        method: "PATCH",
+        body: JSON.stringify({ hidden, reason }),
+      }
+    );
+  },
 };