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>

api/internal/store/store.go

@@ -29,6 +29,24 @@ func (s *Store) Ping(ctx context.Context) error {
 	return s.pool.Ping(ctx)
 }
 
+// PublicStats summarizes the public catalog for the homepage.
+type PublicStats struct {
+	Total     int     `json:"total"`
+	Qualified int     `json:"qualified"`
+	MinScore  float64 `json:"min_score"`
+}
+
+// Stats returns active-product totals and the number of qualified records whose
+// quality_score meets minScore.
+func (s *Store) Stats(ctx context.Context, minScore float64) (PublicStats, error) {
+	st := PublicStats{MinScore: minScore}
+	err := s.pool.QueryRow(ctx, `
+SELECT count(*) FILTER (WHERE status = 'active'),
+       count(*) FILTER (WHERE status = 'active' AND quality_score >= $1)
+FROM product`, minScore).Scan(&st.Total, &st.Qualified)
+	return st, err
+}
+
 // Barcode is one GS1 trade item number attached to a product.
 type Barcode struct {
 	GTIN      string  `json:"gtin"`