上传文件上下文长度限制如何解开?

[DaisyHunter]

• 我已确认目前没有类似 issue
• 我已确认我已升级到最新版本
• 我已完整浏览项目 README 和项目文档并未找到解决方案
• 我理解并愿意跟进此 issue，协助测试和提供反馈
• 我将以礼貌和尊重的态度提问，不得使用不文明用语 (包括在此发布评论的所有人同样适用, 不遵守的人将被 block)
• 我理解并认可上述内容，并理解项目维护者精力有限，不遵循规则的 issue 可能会被无视或直接关闭

问题描述
上传的文件遇到了上下文长度限制，请问这是Blob Service的问题还是ChatNio的问题，应该如何修改限制呢？

复现步骤

1. 上传一个PDF
2. 报告上下文长度限制
3. 文本被截断

预期结果
文本被完整获取。

日志信息

相关截图 (如果有)

[Issues-translate-bot]

Bot detected the issue body's language is not English, translate it automatically.

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Title: How to untie the context length limit of uploading files?

• I have confirmed that there is currently no similar issue
• I have confirmed that I have upgraded to the latest version
• I have fully browsed the project README and project documentation and found no solution
• I understand and am willing to follow up on this issue, assist in testing and provide feedback
• I will ask questions with politeness and respect and shall not use uncivilized terms (the same applies to all those who post comments here, and those who do not comply will be blocked)
• I understand and acknowledge the above and understand that project maintainers have limited energy and that non-compliance with the rules may be ignored or closed directly**

Problem Description
The uploaded file encountered a context length limit. Is this a problem with Blob Service or a problem with ChatNio? How should I modify the limit?

Reproduction steps

1. Upload a PDF
2. Report context length limit
3. Text is truncated

Expected results
The text is retrieved in full.

Log information

Related screenshots (if any)

[SpiralTower]

pdf里有图片会直接转码成base64，直接上传，无论当前模型是不是多模态。等待开源v4看看能不能解决吧

[Issues-translate-bot]

Bot detected the issue body's language is not English, translate it automatically.

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The pictures in pdf will be directly transcoded into base64 and uploaded directly, regardless of whether the current model is multimodal or not. Wait for open source v4 to see if it can be solved