拆分系统配置 Service 文件职责

backend/internal/modules/systemconfig/service_update.go

@@ -0,0 +1,15 @@
+package systemconfig
+
+import (
+	"context"
+)
+
+func (s *Service) Update(ctx context.Context, actorID uint64, key string, req UpdateRequest, meta AuditMeta) (*ConfigDTO, error) {
+	if s.repo == nil {
+		return nil, ErrDependencyUnavailable
+	}
+	if key == "" || req.Value == "" {
+		return nil, ErrInvalidConfig
+	}
+	return s.repo.Update(ctx, actorID, key, req, meta)
+}