fix: gofmt formatting

backend/internal/service/gateway_service.go

@@ -60,7 +60,6 @@ const (
 	claudeMimicDebugInfoKey = "claude_mimic_debug_info"
 )
 
-
 // ForceCacheBillingContextKey 强制缓存计费上下文键
 // 用于粘性会话切换时，将 input_tokens 转为 cache_read_input_tokens 计费
 type forceCacheBillingKeyType struct{}