sendMessage
Send a text message to a chatQueues a plain-text WhatsApp message from this device. chatId is the recipient number in international format (digits only) or a full JID. Implementation is stubbed until messaging is connected.
Example
curl -X POST https://your-host/api/u_YOUR_USER_UID/m_YOUR_DEVICE_UID \
-H "Content-Type: application/json" \
-d '{"command":"sendMessage","params":{"chatId":"972501234567","text":"Hello from MyAPI"}}'