feat(qqbot): add media attachment support for voice/image/video/file

[Allonz]

Summary

Add native media attachment support for QQ Bot platform, enabling voice, image, video, and file sending via send_message tool.

Changes

• Media upload support: Upload media files via QQ Bot v2 REST API before sending
• Chat type detection: Support c2c:<openid> (private chat) and group:<group_openid> (group chat) target formats
• File type mapping: Automatically detect file type from extension:
  • 1 = image (png/jpg/jpeg/gif)
  • 2 = video (mp4/mov/avi)
  • 3 = voice (mp3/wav/flac/silk/amr)
  • 4 = file (default)
• API endpoints:
  • C2C upload: POST /v2/users/{openid}/files
  • Group upload: POST /v2/groups/{group_openid}/files
• Message payload: Include media.file_info field when media is attached

Usage

# Send voice message to QQ user
send_message(target="qqbot:c2c:USER_OPENID", message="MEDIA:/path/to/voice.mp3")

# Send image to QQ group  
send_message(target="qqbot:group:GROUP_OPENID", message="Check this out! MEDIA:/path/to/image.png")

Notes

• Guild channel media upload not yet supported (uses different API)
• Uses same media_files parameter pattern as other platforms (telegram, discord, yuanbao, etc.)

[Allonz]

where is some bugs in this PR,sorry,I will fix them and commit new PR up