feat(backend): 增强使用统计和API密钥功能

- 优化使用统计处理逻辑
- 增强API密钥仓储层功能
- 改进账户使用服务
- 完善API契约测试覆盖

backend/internal/service/api_key_service.go

@@ -34,6 +34,7 @@ type ApiKeyRepository interface {
 	Delete(ctx context.Context, id int64) error
 
 	ListByUserID(ctx context.Context, userID int64, params pagination.PaginationParams) ([]ApiKey, *pagination.PaginationResult, error)
+	VerifyOwnership(ctx context.Context, userID int64, apiKeyIDs []int64) ([]int64, error)
 	CountByUserID(ctx context.Context, userID int64) (int64, error)
 	ExistsByKey(ctx context.Context, key string) (bool, error)
 	ListByGroupID(ctx context.Context, groupID int64, params pagination.PaginationParams) ([]ApiKey, *pagination.PaginationResult, error)
@@ -256,6 +257,18 @@ func (s *ApiKeyService) List(ctx context.Context, userID int64, params paginatio
 	return keys, pagination, nil
 }
 
+func (s *ApiKeyService) VerifyOwnership(ctx context.Context, userID int64, apiKeyIDs []int64) ([]int64, error) {
+	if len(apiKeyIDs) == 0 {
+		return []int64{}, nil
+	}
+
+	validIDs, err := s.apiKeyRepo.VerifyOwnership(ctx, userID, apiKeyIDs)
+	if err != nil {
+		return nil, fmt.Errorf("verify api key ownership: %w", err)
+	}
+	return validIDs, nil
+}
+
 // GetByID 根据ID获取API Key
 func (s *ApiKeyService) GetByID(ctx context.Context, id int64) (*ApiKey, error) {
 	apiKey, err := s.apiKeyRepo.GetByID(ctx, id)