Send content back to the IM conversation that initiated this session.

This is the single outbound IM tool entrypoint. It routes by the gateway session bound to the current run:
- Feishu sessions send to the bound Feishu chat.
- WeChat sessions send to the matching WeChat peer conversation.

You must provide at least one of `text` or `file_path`.

`file_path` may be quoted, include `~` or environment variables, and may resolve from:
- the current workspace
- an absolute local path
- the current process working directory

When both `text` and `file_path` are provided, the tool sends both to the current IM conversation.
