fix: Update specs, add background response job implementation for copilot threads (#11600)

- Enable jobs by default when a copilot thread or a message is created.
- Rename thread_id to copilot_thread_id to keep it consistent with the
model name
- Add a spec for search_linear_issues service

spec/factories/categories.rb

@@ -1,9 +1,10 @@
 FactoryBot.define do
   factory :category, class: 'Category' do
-    portal { portal }
+    portal
     name { 'MyString' }
     description { 'MyText' }
     position { 1 }
+    slug { name.parameterize }
 
     after(:build) do |category|
       category.account ||= category.portal.account