fix: allow free email providers during installation onboarding

Installation onboarding creates the first super-admin via AccountBuilder,
which routes through SignUpEmailValidationService. Without an opt-out, a
self-hoster setting up Chatwoot with a gmail/outlook admin email would
be rejected at install time — a regression for a flow that has nothing
to do with public abuse signals.

Adds an allow_free_email_provider keyword to the service and plumbs it
through AccountBuilder. The public signup paths (api/v1/accounts and
the omniauth callback) continue to enforce the check by default; only
the onboarding controller opts out.

app/builders/account_builder.rb

@@ -2,7 +2,8 @@
 
 class AccountBuilder
   include CustomExceptions::Account
-  pattr_initialize [:account_name, :email!, :confirmed, :user, :user_full_name, :user_password, :super_admin, :locale]
+  pattr_initialize [:account_name, :email!, :confirmed, :user, :user_full_name, :user_password, :super_admin, :locale,
+                    :allow_free_email_provider]
 
   def perform
     if @user.nil?
@@ -32,7 +33,7 @@ class AccountBuilder
   end
 
   def validate_email
-    Account::SignUpEmailValidationService.new(@email).perform
+    Account::SignUpEmailValidationService.new(@email, allow_free_email_provider: @allow_free_email_provider).perform
   end
 
   def validate_user

app/controllers/installation/onboarding_controller.rb

@@ -11,7 +11,8 @@ class Installation::OnboardingController < ApplicationController
         email: onboarding_params.dig(:user, :email),
         user_password: params.dig(:user, :password),
         super_admin: true,
-        confirmed: true
+        confirmed: true,
+        allow_free_email_provider: true
       ).perform
     rescue StandardError => e
       redirect_to '/', flash: { error: e.message } and return

app/services/account/sign_up_email_validation_service.rb

@@ -4,8 +4,9 @@ class Account::SignUpEmailValidationService
   include CustomExceptions::Account
   attr_reader :email
 
-  def initialize(email)
+  def initialize(email, allow_free_email_provider: false)
     @email = email
+    @allow_free_email_provider = allow_free_email_provider
   end
 
   def perform
@@ -17,7 +18,7 @@ class Account::SignUpEmailValidationService
 
     raise InvalidEmail.new({ valid: true, disposable: true }) if address.disposable?
 
-    raise InvalidEmail.new({ free_email_provider: true }) if address.deny_listed?
+    raise InvalidEmail.new({ free_email_provider: true }) if !@allow_free_email_provider && address.deny_listed?
 
     true
   end

spec/builders/account_builder_spec.rb

@@ -20,7 +20,7 @@ RSpec.describe AccountBuilder do
 
   # Mock the email validation service
   before do
-    allow(Account::SignUpEmailValidationService).to receive(:new).with(email).and_return(validation_service)
+    allow(Account::SignUpEmailValidationService).to receive(:new).with(email, allow_free_email_provider: anything).and_return(validation_service)
   end
 
   describe '#perform' do

spec/services/account/sign_up_email_validation_service_spec.rb

@@ -121,5 +121,16 @@ RSpec.describe Account::SignUpEmailValidationService, type: :service do
         expect(error.message).to eq(I18n.t('errors.signup.disposable_email'))
       end
     end
+
+    it 'allows free email providers when allow_free_email_provider is true' do
+      expect(described_class.new('admin@gmail.com', allow_free_email_provider: true).perform).to be(true)
+    end
+
+    it 'still rejects disposable emails even when allow_free_email_provider is true' do
+      expect { described_class.new('user@mailinator.com', allow_free_email_provider: true).perform }.to raise_error do |error|
+        expect(error.class.name).to eq('CustomExceptions::Account::InvalidEmail')
+        expect(error.message).to eq(I18n.t('errors.signup.disposable_email'))
+      end
+    end
   end
 end