Restructure omni services and add Chatwoot research snapshot

research/chatwoot/app/services/whatsapp/phone_normalizers/argentina_phone_normalizer.rb

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+# Handles Argentina phone number normalization
+#
+# Argentina phone numbers can appear with or without "9" after country code
+# This normalizer removes the "9" when present to create consistent format: 54 + area + number
+class Whatsapp::PhoneNormalizers::ArgentinaPhoneNormalizer < Whatsapp::PhoneNormalizers::BasePhoneNormalizer
+  def normalize(waid)
+    return waid unless handles_country?(waid)
+
+    # Remove "9" after country code if present (549 → 54)
+    waid.sub(/^549/, '54')
+  end
+
+  private
+
+  def country_code_pattern
+    /^54/
+  end
+end

research/chatwoot/app/services/whatsapp/phone_normalizers/base_phone_normalizer.rb

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+# Base class for country-specific phone number normalizers
+# Each country normalizer should inherit from this class and implement:
+# - country_code_pattern: regex to identify the country code
+# - normalize: logic to convert phone number to normalized format for contact lookup
+class Whatsapp::PhoneNormalizers::BasePhoneNormalizer
+  def handles_country?(waid)
+    waid.match(country_code_pattern)
+  end
+
+  def normalize(waid)
+    raise NotImplementedError, 'Subclasses must implement #normalize'
+  end
+
+  private
+
+  def country_code_pattern
+    raise NotImplementedError, 'Subclasses must implement #country_code_pattern'
+  end
+end

research/chatwoot/app/services/whatsapp/phone_normalizers/brazil_phone_normalizer.rb

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+# Handles Brazil phone number normalization
+# ref: https://github.com/chatwoot/chatwoot/issues/5840
+#
+# Brazil changed its mobile number system by adding a "9" prefix to existing numbers.
+# This normalizer adds the "9" digit if the number is 12 digits (making it 13 digits total)
+# to match the new format: 55 + DDD + 9 + number
+class Whatsapp::PhoneNormalizers::BrazilPhoneNormalizer < Whatsapp::PhoneNormalizers::BasePhoneNormalizer
+  COUNTRY_CODE_LENGTH = 2
+  DDD_LENGTH = 2
+
+  def normalize(waid)
+    return waid unless handles_country?(waid)
+
+    ddd = waid[COUNTRY_CODE_LENGTH, DDD_LENGTH]
+    number = waid[COUNTRY_CODE_LENGTH + DDD_LENGTH, waid.length - (COUNTRY_CODE_LENGTH + DDD_LENGTH)]
+    normalized_number = "55#{ddd}#{number}"
+    normalized_number = "55#{ddd}9#{number}" if normalized_number.length != 13
+    normalized_number
+  end
+
+  private
+
+  def country_code_pattern
+    /^55/
+  end
+end