CLDC-4175: add new question to ui flow

app/models/form/sales/pages/service_charge_changed.rb

@@ -0,0 +1,14 @@
+class Form::Sales::Pages::ServiceChargeChanged < ::Form::Page
+  def initialize(id, hsh, subsection)
+    super
+    @id = "service_charge_changed"
+    @copy_key = "sales.sale_information.servicecharges_changed"
+  end
+
+  def questions
+    @questions ||= [
+      Form::Sales::Questions::HasServiceChargesChanged.new(nil, nil, self),
+      Form::Sales::Questions::NewServiceCharges.new(nil, nil, self),
+    ]
+  end
+end

app/models/form/sales/questions/has_service_charges_changed.rb

@@ -0,0 +1,27 @@
+class Form::Sales::Questions::HasServiceChargesChanged < ::Form::Question
+  def initialize(id, hsh, page)
+    super
+    @id = "hasservicechargeschanged"
+    @type = "radio"
+    @answer_options = ANSWER_OPTIONS
+    @conditional_for = {
+      "newservicecharges" => [1],
+    }
+    @hidden_in_check_answers = {
+      "depends_on" => [
+        {
+          "hasservicechargeschanged" => 1,
+        },
+      ],
+    }
+    @copy_key = "sales.sale_information.servicecharges_changed.has_service_charges_changed"
+    @question_number = QUESTION_NUMBER_FROM_YEAR[form.start_date.year] || QUESTION_NUMBER_FROM_YEAR[QUESTION_NUMBER_FROM_YEAR.keys.max]
+  end
+
+  ANSWER_OPTIONS = {
+    "1" => { "value" => "Yes" },
+    "2" => { "value" => "No" },
+  }.freeze
+
+  QUESTION_NUMBER_FROM_YEAR = { 2026 => 0 }.freeze
+end

app/models/form/sales/questions/new_service_charges.rb

@@ -0,0 +1,17 @@
+class Form::Sales::Questions::NewServiceCharges < ::Form::Question
+  def initialize(id, hsh, page)
+    super
+    @id = "newservicecharges"
+    @type = "numeric"
+    @min = 0
+    @max = 9999.99
+    @step = 0.01
+    @width = 5
+    @prefix = "£"
+    @copy_key = "sales.sale_information.servicecharges_changed.new_service_charges"
+    @question_number = QUESTION_NUMBER_FROM_YEAR[form.start_date.year] || QUESTION_NUMBER_FROM_YEAR[QUESTION_NUMBER_FROM_YEAR.keys.max]
+    @strip_commas = true
+  end
+
+  QUESTION_NUMBER_FROM_YEAR = { 2026 => 0 }.freeze
+end

app/models/form/sales/subsections/shared_ownership_staircasing_transaction.rb

@@ -26,6 +26,7 @@ class Form::Sales::Subsections::SharedOwnershipStaircasingTransaction < ::Form::
       Form::Sales::Pages::MonthlyRentStaircasingOwned.new(nil, nil, self),
       Form::Sales::Pages::MonthlyRentStaircasing.new(nil, nil, self),
       (Form::Sales::Pages::ServiceChargeStaircasing.new("service_charge_staircasing", nil, self) if form.start_year_2026_or_later?),
+      (Form::Sales::Pages::ServiceChargeChanged.new(nil, nil, self) if form.start_year_2026_or_later?),
       Form::Sales::Pages::MonthlyChargesValueCheck.new("monthly_charges_shared_ownership_value_check", nil, self),
     ].compact
   end