Fix soft-delete cascade for contact topic answers (#6837)

Add `acts_as_paranoid` to `ContactTopicAnswer` and add `deleted_at` column via migration to support soft deletion.

Author: alanparmenter

app/models/contact_topic_answer.rb

@@ -1,6 +1,7 @@
 class ContactTopicAnswer < ApplicationRecord
   belongs_to :case_contact
   belongs_to :contact_topic, optional: true
+  acts_as_paranoid
 
   has_one :casa_case, through: :case_contact
   has_one :casa_org, through: :case_contact
@@ -17,6 +18,7 @@ class ContactTopicAnswer < ApplicationRecord
 # Table name: contact_topic_answers
 #
 #  id               :bigint           not null, primary key
+#  deleted_at       :datetime
 #  selected         :boolean          default(FALSE), not null
 #  value            :text
 #  created_at       :datetime         not null

db/migrate/20260414132818_add_deleted_at_to_contact_topic_answers.rb

@@ -0,0 +1,5 @@
+class AddDeletedAtToContactTopicAnswers < ActiveRecord::Migration[7.2]
+  def change
+    add_column :contact_topic_answers, :deleted_at, :datetime
+  end
+end

db/schema.rb

@@ -10,7 +10,7 @@
 #
 # It's strongly recommended that you check this file into your version control system.
 
-ActiveRecord::Schema[7.2].define(version: 2026_02_11_001655) do
+ActiveRecord::Schema[7.2].define(version: 2026_04_14_132818) do
   # These are extensions that must be enabled in order to support this database
   enable_extension "plpgsql"
 
@@ -259,6 +259,7 @@
     t.boolean "selected", default: false, null: false
     t.datetime "created_at", null: false
     t.datetime "updated_at", null: false
+    t.datetime "deleted_at"
     t.index ["case_contact_id"], name: "index_contact_topic_answers_on_case_contact_id"
   end