Fix wecomcs open_kfid msgid

[DeepCodeYang]

概述 / Overview

/src/langbot/pkg/platform/sources/wecomcs.py
针对企业微信客服人工接管主动发送消息报错，修复了两处内容：

1. send_message 调用时无法获取open_kid，在 wecomcs.py 中找到 WecomEventConverter 类的 target2yiri 方法，将处理 text
   和 image 事件时的 friend处代码，将id补充前缀 event.receiver_id (即 open_kfid)。

2. msgid 长度超限：企业微信客服 API 官方文档明确规定，主动发送消息时的 msgid（消息 ID）最大长度不能超过 32 字节，由于uuid.uuid4().hex 本身已经是 32 个字符，于是把langbot_前缀去掉。
   【补充企业微信官方文档地址：】https://developer.work.weixin.qq.com/document/path/94700
   并且在文字text类型下方增加了对图片类型image的支持。

更改前后对比截图 / Screenshots

请在此部分粘贴更改前后对比截图（可以是界面截图、控制台输出、对话截图等）:
Please paste the screenshots of changes before and after here (can be interface screenshots, console output, conversation screenshots, etc.):

修改前 / Before:
请求信息：
{page_id: "console", endpoint: "/reply", method: "POST", body: {session_key: "person_uwmJ2Y5ZgAAfaenjtZtOgT2KO14nyuTvg", text: "你好", image_base64: "", file_base64: "", file_name: ""}}
响应/报错信息：
{code: -1, msg: "ActionCallError: Exception: Failed t
o send message"}
修改后 / After:

检查清单 / Checklist

PR 作者完成 / For PR author

请在方括号间写x以打勾 / Please tick the box with x

• 阅读仓库贡献指引了吗？ / Have you read the contribution guide?
• 我已签署或将在机器人提示后签署 CLA。 / I have signed, or will sign when prompted by the bot, the CLA.
• 与项目所有者沟通过了吗？ / Have you communicated with the project maintainer?
• 我确定已自行测试所作的更改，确保功能符合预期。 / I have tested the changes and ensured they work as expected.

项目维护者完成 / For project maintainer

• 相关 issues 链接了吗？ / Have you linked the related issues?
• [Bug]: 提供一个企业微信适配器的bug(已处理分享出来)（企业微信客服） #2421
• 配置项写好了吗？迁移写好了吗？生效了吗？ / Have you written the configuration items? Have you written the migration? Has it taken effect?
• 依赖加到 pyproject.toml 和 core/bootutils/deps.py 了吗 / Have you added the dependencies to pyproject.toml and core/bootutils/deps.py?
• 文档编写了吗？ / Have you written the documentation?

[github-actions]

All contributors have signed the CLA. ✅ 所有贡献者均已签署 CLA。
_{Posted by the CLA Assistant Lite bot.}

[DeepCodeYang]

I have read the CLA Document and I hereby sign the CLA

[RockChinQ]

Hi @DeepCodeYang , please fix the unit test issues.

[codecov]

Codecov Report

❌ Patch coverage is 73.68421% with 5 lines in your changes missing coverage. Please review.

Files with missing lines	Patch %	Lines
src/langbot/libs/wecom_customer_service_api/api.py	68.75%	5 Missing ⚠️

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