feat: 数据概览/操作日志/批量操作 + 首页合格档案数

后台新增「数据概览」(商品/合格/按状态/品牌/分类/待审核) 与「操作日志」(全局审计分页)；商品列表支持多选批量改状态/分类。公开首页标题改为「天工」并展示合格档案数；新增公开接口 /api/v1/stats 与后台 /api/stats、/api/audit、/api/products/bulk。合格口径=quality_score≥0.6 且在用。

Co-Authored-By: Devin AI <158243242+devin-ai-integration[bot]@users.noreply.github.com>

admin-frontend/src/api.ts

@@ -171,4 +171,22 @@ export const api = {
     ),
   revokeApiKey: (id: string) =>
     request<{ status: string }>(`/keys/${id}`, { method: "DELETE" }),
+  stats: () => request<import("./types").AdminStats>("/stats"),
+  auditLog: (page: number, size: number) =>
+    request<{
+      items: import("./types").AuditLogRow[];
+      page: number;
+      size: number;
+      total: number;
+    }>(`/audit?page=${page}&size=${size}`),
+  bulkProducts: (body: {
+    ids: string[];
+    action: "status" | "category";
+    status?: string;
+    category_id?: string | null;
+  }) =>
+    request<{ status: string; affected: number }>("/products/bulk", {
+      method: "POST",
+      body: JSON.stringify(body),
+    }),
 };