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/adminstore/write.go

@@ -481,6 +481,44 @@ type AuditEntry struct {
 	CreatedAt string   `json:"created_at"`
 }
 
+// AuditLogRow is one global audit-log row for the operations log view.
+type AuditLogRow struct {
+	ID        string   `json:"id"`
+	Actor     string   `json:"actor"`
+	Action    string   `json:"action"`
+	Entity    string   `json:"entity"`
+	EntityID  *string  `json:"entity_id"`
+	Fields    []string `json:"fields"`
+	CreatedAt string   `json:"created_at"`
+}
+
+// ListAllAudit returns a page of the global audit log, newest first, along with
+// the total row count.
+func (s *Store) ListAllAudit(ctx context.Context, limit, offset int) ([]AuditLogRow, int, error) {
+	var total int
+	if err := s.pool.QueryRow(ctx, "SELECT count(*) FROM audit_log").Scan(&total); err != nil {
+		return nil, 0, err
+	}
+	rows, err := s.pool.Query(ctx, `
+SELECT id, actor, action, entity, entity_id::text, fields, created_at::text
+FROM audit_log
+ORDER BY created_at DESC
+LIMIT $1 OFFSET $2`, limit, offset)
+	if err != nil {
+		return nil, 0, err
+	}
+	defer rows.Close()
+	out := []AuditLogRow{}
+	for rows.Next() {
+		var e AuditLogRow
+		if err := rows.Scan(&e.ID, &e.Actor, &e.Action, &e.Entity, &e.EntityID, &e.Fields, &e.CreatedAt); err != nil {
+			return nil, 0, err
+		}
+		out = append(out, e)
+	}
+	return out, total, rows.Err()
+}
+
 // ListAudit returns audit history for one product, newest first.
 func (s *Store) ListAudit(ctx context.Context, productID string, limit int) ([]AuditEntry, error) {
 	rows, err := s.pool.Query(ctx, `