Connect WhatsApp via credentials

Connect a WhatsApp Business Account by providing Meta credentials directly. This is the headless alternative to the Embedded Signup browser flow. To get the required credentials: 1. Go to Meta Business Suite (business.facebook.com) 2. Create or select a WhatsApp Business Account 3. In Business Settings > System Users, create a System User 4. Assign it the `whatsapp_business_management` and `whatsapp_business_messaging` permissions 5. Generate a permanent access token 6. Get the WABA ID from WhatsApp Manager > Account Tools > Phone Numbers 7. Get the Phone Number ID from the same page (click on the number)

curl -X POST "https://getlate.dev/api/v1/connect/whatsapp/credentials" \  -H "Content-Type: application/json" \  -d '{    "profileId": "6507a1b2c3d4e5f6a7b8c9d0",    "accessToken": "EAABsbCS...your-system-user-token",    "wabaId": "123456789012345",    "phoneNumberId": "987654321098765"  }'

{
  "message": "WhatsApp connected successfully",
  "account": {
    "accountId": "6507a1b2c3d4e5f6a7b8c9d0",
    "platform": "whatsapp",
    "username": "+1 555-123-4567",
    "displayName": "Acme Corp",
    "isActive": true,
    "phoneNumber": "+1 555-123-4567",
    "verifiedName": "Acme Corp",
    "qualityRating": "GREEN"
  }
}