feat: Sites feature backend

internal/infrastructure/useCases/siteImageUsage.go

@@ -0,0 +1,17 @@
+package useCases
+
+import "RenewCMS/internal/domain/site"
+
+func siteImageUsage(sites site.Repository) (map[uint32]int, error) {
+	usage := map[uint32]int{}
+	all, err := sites.List()
+	if err != nil {
+		return nil, err
+	}
+	for _, s := range all {
+		if s.DefaultSocialImageID != nil {
+			usage[*s.DefaultSocialImageID]++
+		}
+	}
+	return usage, nil
+}