feat: add Captain::Scenario Model and API [CW-4597] (#11907)

Co-authored-by: Muhsin Keloth <muhsinkeramam@gmail.com>

spec/factories/captain/scenario.rb

@@ -0,0 +1,11 @@
+FactoryBot.define do
+  factory :captain_scenario, class: 'Captain::Scenario' do
+    sequence(:title) { |n| "Scenario #{n}" }
+    description { 'Test scenario description' }
+    instruction { 'Test scenario instruction for the assistant to follow' }
+    tools { [] }
+    enabled { true }
+    association :assistant, factory: :captain_assistant
+    association :account
+  end
+end