Add task for migrating teams

This sets up our three organisations with their new schools and new team
structure ready for the 2025/26 academic year.

I've created classes to make the necessary changes, and added some basic
tests, although I expect this code to be temporary and deleted after it
has been run.

Jira-Issue: MAV-1664

Author: thomasleese

app/lib/team_migration/base.rb

@@ -0,0 +1,78 @@
+# frozen_string_literal: true
+
+class TeamMigration::Base
+  def call
+    ActiveRecord::Base.transaction { perform }
+  end
+
+  def self.call(...) = new(...).call
+
+  private_class_method :new
+
+  protected
+
+  def log(message) = Rails.logger.debug("#{ods_code}: #{message}")
+
+  def create_team(workgroup:, **attributes)
+    log("Creating team #{workgroup}")
+    team = organisation.teams.create!(workgroup:, **attributes)
+    GenericClinicFactory.call(team:)
+    team
+  end
+
+  def destroy_team(team)
+    team.programmes.destroy_all
+    team.subteams.destroy_all
+    team.destroy!
+  end
+
+  def add_team_programmes(team, *programme_types)
+    programme_types.each do |type|
+      log("Adding #{type} programme to #{team.workgroup}")
+      programme = Programme.find_by!(type:)
+      team.programmes << programme
+    end
+
+    GenericClinicFactory.call(team:)
+  end
+
+  def set_team_workgroup(team, workgroup)
+    log("Setting #{team.name} workgroup to #{workgroup}")
+    team.update_column(:workgroup, workgroup)
+  end
+
+  def attach_school_to_subteam(location, subteam)
+    log("Attaching #{location.urn} to #{subteam.name}")
+    location.sessions.update_all(team_id: subteam.team_id)
+    location.update!(subteam:)
+  end
+
+  def attach_school_to_team(location, team)
+    attach_school_to_subteam(location, team.subteams.first)
+  end
+
+  def add_school_year_groups(location, programmes, sen:)
+    log(
+      "Adding default #{programmes.map(&:name).to_sentence} year groups to #{location.urn}"
+    )
+    location.location_programme_year_groups.destroy_all
+    location.create_default_programme_year_groups!(programmes)
+
+    log("Adding additional flu year groups to #{location.urn}")
+    if sen && (programme = programmes.find(&:flu?))
+      location
+        .year_groups
+        .select { it >= 12 }
+        .each do |year_group|
+          location.location_programme_year_groups.create!(
+            programme:,
+            year_group:
+          )
+        end
+    end
+  end
+
+  def organisation
+    @organisation ||= Organisation.find_by!(ods_code:)
+  end
+end