fix(provider): 火山方舟图片 - 避免结果下载重复计费

集成 PR #256，保留原 PR 开发者为提交作者。

web/src/services/api/image.ts

@@ -919,6 +919,7 @@ export async function requestGeneration(config: AiConfig, prompt: string, option
                   model: requestConfig.model,
                   prompt: withSystemPrompt(requestConfig, prompt),
                   n,
+                  response_format: "b64_json",
                   watermark: false,
                   ...(normalizedRequestSize ? { [normalizedRequestSize.parameter]: normalizedRequestSize.value } : {}),
               }
@@ -1014,6 +1015,7 @@ export async function requestEdit(config: AiConfig, prompt: string, references:
                     model: requestConfig.model,
                     prompt: withSystemPrompt(requestConfig, requestPrompt),
                     n,
+                    response_format: "b64_json",
                     watermark: false,
                     ...(requestSize ? { [requestSize.parameter]: requestSize.value } : {}),
                     ...(images.length === 1 ? { image: images[0] } : images.length > 1 ? { image: images } : {}),