- Add comprehensive guide for integrating WhatsApp Business API using Twilio phone numbers
- Include complete workflow: from number purchase to Meta configuration
- Add 5 detailed guides: quick-start, webhooks, examples, troubleshooting, quick-reference
- Cover phone number verification via voice call (Twilio requirement)
- Document all Meta credentials: Access Token, Phone Number ID, WABA ID, Verify Token, Application ID
- Provide code examples in BASIC, Node.js, and Python
- Integrate into Appendix B: External Services (no new chapter)
- All example values randomized for security
