post https://waapi.app/api/v1/instances//client/action/send-message
Send a text message to a chat. The chatId format varies depending on the chat type:
- Individual chat: {phone_number}@c.us (e.g. [email protected])
- Group chat: {group_id}@g.us (e.g. [email protected])
- Channel/Newsletter: {channel_id}@newsletter (e.g. 123456789@newsletter)