Currently `send_message` only supports text. Users can't send images, videos, or documents.
What to do:
- Add a `send_file` tool that accepts a file path and recipient JID
- Use `client.Upload(ctx, bytes, MediaType)` to encrypt and upload
- Then `SendMessage()` with the appropriate message type (ImageMessage, VideoMessage, DocumentMessage)
- Auto-detect MIME type from file extension
- Support optional caption
whatsmeow's `Upload()` + `SendMessage()` handles the full flow.
Currently `send_message` only supports text. Users can't send images, videos, or documents.
What to do:
whatsmeow's `Upload()` + `SendMessage()` handles the full flow.