fix(test): add IncrementQuotaUsed to all APIKeyRepository test stubs

- Add missing IncrementQuotaUsed method to stubApiKeyRepo in api_contract_test.go
- Fix gofmt formatting issues in api_key_service.go, dto/types.go, api_key_handler.go

backend/internal/handler/api_key_handler.go

@@ -29,11 +29,11 @@ func NewAPIKeyHandler(apiKeyService *service.APIKeyService) *APIKeyHandler {
 // CreateAPIKeyRequest represents the create API key request payload
 type CreateAPIKeyRequest struct {
 	Name          string   `json:"name" binding:"required"`
-	GroupID       *int64   `json:"group_id"`       // nullable
-	CustomKey     *string  `json:"custom_key"`     // 可选的自定义key
-	IPWhitelist   []string `json:"ip_whitelist"`   // IP 白名单
-	IPBlacklist   []string `json:"ip_blacklist"`   // IP 黑名单
-	Quota         *float64 `json:"quota"`          // 配额限制 (USD)
+	GroupID       *int64   `json:"group_id"`        // nullable
+	CustomKey     *string  `json:"custom_key"`      // 可选的自定义key
+	IPWhitelist   []string `json:"ip_whitelist"`    // IP 白名单
+	IPBlacklist   []string `json:"ip_blacklist"`    // IP 黑名单
+	Quota         *float64 `json:"quota"`           // 配额限制 (USD)
 	ExpiresInDays *int     `json:"expires_in_days"` // 过期天数
 }