feat(web): admin flagged-listings moderation dashboard (GOO-160)

Add admin dashboard pages for reviewing and acting on user-flagged listings,
backed by the GOO-159 admin-moderation API surface (list/detail/moderate).

Pages:
- /admin/moderation/flagged — paginated, URL-synced filterable table with
  sortable columns (flag count, latest flag, created at), reason/status/date
  filters, bulk select + sticky action bar (dismiss / suspend / warn).
- /admin/moderation/flagged/[id] — listing summary, photo grid, seller card,
  full reporter list, per-listing action buttons mirroring bulk actions.

All actions go through a confirmation Dialog with optional moderator note.
Vietnamese UI throughout. Loading / empty / error / optimistic states
covered. Imports the existing admin layout via the (admin) route group.

Adds typed API surface in lib/admin-api.ts:
  getFlaggedListings, getFlaggedListingDetail, moderateFlaggedListings
plus FlagReason / FlagStatus / FlaggedAction / FlaggedSortBy and
request/response interfaces.

E2E (Playwright) at e2e/web/admin-moderation-flagged.spec.ts mocks the three
endpoints and covers: list filter + bulk dismiss happy path, detail view
with reporters + suspend action, and the empty state.

Co-Authored-By: Paperclip <noreply@paperclip.ing>

apps/web/lib/admin-api.ts

@@ -242,8 +242,107 @@ export const adminApi = {
 
   provisionParkOperator: (body: ProvisionParkOperatorPayload) =>
     apiClient.post<ProvisionAccountResult>('/admin/accounts/park-operators', body),
+
+  // ── Flagged listings (user reports) ──
+  getFlaggedListings: (params: FlaggedListingsQueryParams = {}) => {
+    const q = new URLSearchParams();
+    if (params.page) q.set('page', String(params.page));
+    if (params.limit) q.set('limit', String(params.limit));
+    if (params.reason) q.set('reason', params.reason);
+    if (params.dateFrom) q.set('dateFrom', params.dateFrom);
+    if (params.dateTo) q.set('dateTo', params.dateTo);
+    if (params.listingStatus) q.set('listingStatus', params.listingStatus);
+    if (params.flagCountMin !== undefined) q.set('flagCountMin', String(params.flagCountMin));
+    if (params.sortBy) q.set('sortBy', params.sortBy);
+    if (params.sortOrder) q.set('sortOrder', params.sortOrder);
+    const qs = q.toString();
+    return apiClient.get<PaginatedFlaggedListingsResult>(
+      `/admin/listings/flagged${qs ? `?${qs}` : ''}`,
+    );
+  },
+
+  getFlaggedListingDetail: (listingId: string) =>
+    apiClient.get<FlaggedListingDetail>(`/admin/listings/${listingId}/flags`),
+
+  moderateFlaggedListings: (body: ModerateFlaggedListingsPayload) =>
+    apiClient.post<ModerateFlaggedListingsResult>('/admin/listings/moderate', body),
 };
 
+// ── Flagged listings types ──
+
+export type FlagReason = 'SCAM' | 'DUPLICATE' | 'WRONG_INFO' | 'ALREADY_SOLD' | 'INAPPROPRIATE';
+export type FlagStatus = 'PENDING' | 'REVIEWED' | 'DISMISSED';
+export type FlaggedAction = 'dismiss_flags' | 'suspend_listing' | 'warn_seller';
+export type FlaggedSortBy = 'flagCount' | 'latestFlagAt' | 'createdAt';
+
+export interface FlaggedListingsQueryParams {
+  page?: number;
+  limit?: number;
+  reason?: FlagReason;
+  dateFrom?: string;
+  dateTo?: string;
+  listingStatus?: string;
+  flagCountMin?: number;
+  sortBy?: FlaggedSortBy;
+  sortOrder?: 'asc' | 'desc';
+}
+
+export interface FlaggedListingItem {
+  listingId: string;
+  propertyTitle: string;
+  sellerName: string;
+  status: string;
+  totalReports: number;
+  reasons: FlagReason[];
+  latestReportAt: string;
+}
+
+export interface PaginatedFlaggedListingsResult {
+  items: FlaggedListingItem[];
+  total: number;
+  page: number;
+  limit: number;
+}
+
+export interface FlaggedListingDetailFlag {
+  id: string;
+  reason: FlagReason;
+  description: string | null;
+  status: FlagStatus;
+  reporter: { id: string; fullName: string };
+  createdAt: string;
+}
+
+export interface FlaggedListingDetail {
+  listing: {
+    id: string;
+    title: string;
+    status: string;
+    priceVND: number;
+    propertyType: string;
+    transactionType: string;
+    photos: string[];
+    createdAt: string;
+    seller: { id: string; fullName: string; email: string | null; phone: string };
+  };
+  flags: FlaggedListingDetailFlag[];
+  totalReports: number;
+  distinctReasons: FlagReason[];
+}
+
+export interface ModerateFlaggedListingsPayload {
+  listingIds: string[];
+  action: FlaggedAction;
+  note?: string;
+}
+
+export interface ModerateFlaggedListingsResult {
+  processed: number;
+  skipped: number;
+  succeeded?: string[];
+  failed?: Array<{ listingId: string; reason: string }>;
+}
+
 export interface ProvisionDeveloperPayload {
   phone: string;
   password: string;