## Summary
This fixes WhatsApp phone number normalization for Mexico numbers when
using Twilio as a provider.
Twilio may send incoming Mexico WhatsApp phone numbers with an extra `1`
after the country code, for example:
- stored contact inbox source: `whatsapp:+525512345678`
- incoming message source: `whatsapp:+5215512345678`
Before this change, Chatwoot could treat these as different source IDs
and create a duplicate contact/conversation path instead of matching the
existing one.
## What changed
- added a Mexico-specific phone normalizer
- normalize `+521...` to `+52...` for contact matching
- kept the original incoming source ID when creating a brand new contact
inbox
## Why this approach
Chatwoot already has country-specific normalization for WhatsApp numbers
in the normalization service. This follows the same pattern and keeps
the change small and isolated.
## Tests
Added specs covering:
- matching an existing Mexico WhatsApp contact inbox when Twilio sends
`+521...`
- preserving the original source ID when no matching contact inbox
exists and a new one is created
Fixes
https://linear.app/chatwoot/issue/CW-6844/fix-normalize-mexico-whatsapp-phone-numbers-on-twilio-to-prevent
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Co-authored-by: Muhsin Keloth <muhsinkeramam@gmail.com>
Co-authored-by: Muhsin <12408980+muhsin-k@users.noreply.github.com>
Co-authored-by: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
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