WeCom AI Bot sends file attachments with msgtype="appmsg", not msgtype="file". Previously only file content was discarded while the text title reached the agent. Changes: - _extract_text(): Extract appmsg title (filename) for display - _extract_media(): Handle appmsg type with file/image content Fixes #7750 Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>