feat: add Baileys-based WhatsApp channel (/add-whatsapp-baileys)

[ivo-toby]

Summary

Add an alternative WhatsApp channel implementation using Baileys — the open-source WhatsApp Web multi-device protocol library.

Motivation

The primary WhatsApp channel (/add-whatsapp-cloud) uses the official Meta Cloud API, which requires:

• A Meta Business account
• A paid phone number subscription
• A publicly reachable webhook URL

A Baileys-based channel would:

• Work with any personal WhatsApp account (no Meta Business account needed)
• Require no inbound port / public URL (outbound WebSocket only)
• Be free to run

This is ideal for self-hosters who want to connect a personal WhatsApp account without provisioning a Meta Business API phone number.

Implementation notes

• Use @whiskeysockets/baileys for the WebSocket client
• Auth via QR code or pairing code (stored in store/auth/)
• JID format: PHONE@s.whatsapp.net (DM) / GROUP_ID@g.us (group)
• Self-registration via registerChannel('whatsapp-baileys', factory)
• New skill: /add-whatsapp-baileys

Trade-offs vs Cloud API

	Cloud API	Baileys
Account type	Meta Business	Personal
Cost	Paid at scale	Free
Public webhook needed	Yes	No
Official	Yes	No (reverse-engineered)
Ban risk	None	Possible
Group support	Limited	Full

References

• Baileys repo: https://github.com/WhiskeySockets/Baileys
• Existing nanoclaw-whatsapp (Baileys-based): https://github.com/qwibitai/nanoclaw-whatsapp