Use this if no QR code appears or the WhatsApp session was logged out.
POST /send
Body: { "phone": "919876543210", "message": "Hello!" }
GET /api/send?phone=919876543210&message=Hello!
GET /status - Check connection status
GET /messages?phone=919876543210&limit=100 - Read stored messages for a number
GET /contacts - List contacts with stored messages
POST /logout - Log out and clear this device's session
GET /groups - List all groups
POST /send-group
Body: { "groupId": "123456789@g.us", "message": "Hello!" }
GET /api/send-group?groupId=123456789@g.us&message=Hello!