fix: Extend phone number normalization to Twilio WhatsApp (#12655)

### Problem
WhatsApp Cloud channels already handle Brazil/Argentina phone number
format mismatches (PRs #12492, #11173), but Twilio WhatsApp channels
were creating duplicate contacts
  when:
  - Template sent to new format: `whatsapp:+5541988887777` (13 digits)
  - User responds from old format: `whatsapp:+554188887777` (12 digits)

### Solution

The solution extends the existing phone number normalization
infrastructure to support both WhatsApp providers while handling their
different payload formats:

  ### Provider Format Differences
  - **WhatsApp Cloud**: `wa_id: "919745786257"` (clean number)
- **Twilio WhatsApp**: `From: "whatsapp:+919745786257"` (prefixed
format)
  
  
 ### Test Coverage

#### Brazil Phone Number Tests
  **Case 1: New Format (13 digits with "9")**
- **Test 1**: No existing contact → Creates new contact with original
format
- **Test 2**: Contact exists in same format → Appends to existing
conversation

  **Case 2: Old Format (12 digits without "9")**
- **Test 3**: Contact exists in old format → Appends to existing
conversation
- **Test 4** *(Critical)*: Contact exists in new format, message in old
format → Finds existing contact, prevents duplicate
- **Test 5**: No contact exists → Creates new contact with incoming
format

#### Argentina Phone Number Tests
  **Case 3: With "9" after country code**
  - **Test 6**: No existing contact → Creates new contact
- **Test 7**: Contact exists in normalized format → Uses existing
contact

  **Case 4: Without "9" after country code**
  - **Test 8**: Contact exists in same format → Appends to existing
  - **Test 9**: No contact exists → Creates new contact

Fixes
https://linear.app/chatwoot/issue/CW-5565/inconsistencies-for-mobile-numbersargentina-brazil-and-mexico-numbers

app/services/twilio/incoming_message_service.rb

@@ -44,6 +44,12 @@ class Twilio::IncomingMessageService
     twilio_channel.sms? ? params[:From] : params[:From].gsub('whatsapp:', '')
   end
 
+  def normalized_phone_number
+    return phone_number unless twilio_channel.whatsapp?
+
+    Whatsapp::PhoneNumberNormalizationService.new(inbox).normalize_and_find_contact_by_provider("whatsapp:#{phone_number}", :twilio)
+  end
+
   def formatted_phone_number
     TelephoneNumber.parse(phone_number).international_number
   end
@@ -53,8 +59,10 @@ class Twilio::IncomingMessageService
   end
 
   def set_contact
+    source_id = twilio_channel.whatsapp? ? normalized_phone_number : params[:From]
+
     contact_inbox = ::ContactInboxWithContactBuilder.new(
-      source_id: params[:From],
+      source_id: source_id,
       inbox: inbox,
       contact_attributes: contact_attributes
     ).perform

app/services/whatsapp/incoming_message_service_helpers.rb

@@ -47,17 +47,8 @@ module Whatsapp::IncomingMessageServiceHelpers
     %w[reaction ephemeral unsupported request_welcome].include?(message_type)
   end
 
-  def argentina_phone_number?(phone_number)
-    phone_number.match(/^54/)
-  end
-
-  def normalised_argentina_mobil_number(phone_number)
-    # Remove 9 before country code
-    phone_number.sub(/^549/, '54')
-  end
-
   def processed_waid(waid)
-    Whatsapp::PhoneNumberNormalizationService.new(inbox).normalize_and_find_contact(waid)
+    Whatsapp::PhoneNumberNormalizationService.new(inbox).normalize_and_find_contact_by_provider(waid, :cloud)
   end
 
   def error_webhook_event?(message)

app/services/whatsapp/phone_number_normalization_service.rb

@@ -1,23 +1,32 @@
 # Service to handle phone number normalization for WhatsApp messages
 # Currently supports Brazil and Argentina phone number format variations
-# Designed to be extensible for additional countries in future PRs
-#
-# Usage: Whatsapp::PhoneNumberNormalizationService.new(inbox).normalize_and_find_contact(waid)
+# Supports both WhatsApp Cloud API and Twilio WhatsApp providers
 class Whatsapp::PhoneNumberNormalizationService
   def initialize(inbox)
     @inbox = inbox
   end
 
-  # Main entry point for phone number normalization
-  # Returns the source_id of an existing contact if found, otherwise returns original waid
-  def normalize_and_find_contact(waid)
-    normalizer = find_normalizer_for_country(waid)
-    return waid unless normalizer
+  # @param raw_number [String] The phone number in provider-specific format
+  #   - Cloud: "5541988887777" (clean number)
+  #   - Twilio: "whatsapp:+5541988887777" (prefixed format)
+  # @param provider [Symbol] :cloud or :twilio
+  # @return [String] Normalized source_id in provider format or original if not found
+  def normalize_and_find_contact_by_provider(raw_number, provider)
+    # Extract clean number based on provider format
+    clean_number = extract_clean_number(raw_number, provider)
 
-    normalized_waid = normalizer.normalize(waid)
-    existing_contact_inbox = find_existing_contact_inbox(normalized_waid)
+    # Find appropriate normalizer for the country
+    normalizer = find_normalizer_for_country(clean_number)
+    return raw_number unless normalizer
 
-    existing_contact_inbox&.source_id || waid
+    # Normalize the clean number
+    normalized_clean_number = normalizer.normalize(clean_number)
+
+    # Format for provider and check for existing contact
+    provider_format = format_for_provider(normalized_clean_number, provider)
+    existing_contact_inbox = find_existing_contact_inbox(provider_format)
+
+    existing_contact_inbox&.source_id || raw_number
   end
 
   private
@@ -33,6 +42,26 @@ class Whatsapp::PhoneNumberNormalizationService
     inbox.contact_inboxes.find_by(source_id: normalized_waid)
   end
 
+  # Extract clean number from provider-specific format
+  def extract_clean_number(raw_number, provider)
+    case provider
+    when :twilio
+      raw_number.gsub(/^whatsapp:\+/, '') # Remove prefix: "whatsapp:+5541988887777" → "5541988887777"
+    else
+      raw_number # Default fallback for unknown providers
+    end
+  end
+
+  # Format normalized number for provider-specific storage
+  def format_for_provider(clean_number, provider)
+    case provider
+    when :twilio
+      "whatsapp:+#{clean_number}" # Add prefix: "5541988887777" → "whatsapp:+5541988887777"
+    else
+      clean_number # Default for :cloud and unknown providers: "5541988887777"
+    end
+  end
+
   NORMALIZERS = [
     Whatsapp::PhoneNormalizers::BrazilPhoneNormalizer,
     Whatsapp::PhoneNormalizers::ArgentinaPhoneNormalizer