Add project setting for agent session tracking

Why

We want to be able to trace agent sessions for commits.

We want this to be opt in through a project setting.

What

Add project setting for agent session tracking

Add dap_session_tracking_enabled boolean to project_settings table with feature flag gating and license checks. The setting controls whether agent sessions are referenced in commit messages.

EE: true Changelog: added

MR sequence

I've tried to break this up into small series of changes on the backend to keep the review burden low.

This is MR 1 of that sequence

Database

Click for migration output

Migration output

== 20260514141636 AddDapSessionTrackingEnabledToProjectSettings: migrating ====
-- add_column(:project_settings, :dap_session_tracking_enabled, :boolean, {:default=>false, :null=>false})
   -> 0.0504s
== 20260514141636 AddDapSessionTrackingEnabledToProjectSettings: migrated (0.0585s)

Rollback output


== 20260514141636 AddDapSessionTrackingEnabledToProjectSettings: reverting ====
-- remove_column(:project_settings, :dap_session_tracking_enabled, :boolean, {:default=>false, :null=>false})
   -> 0.0542s
== 20260514141636 AddDapSessionTrackingEnabledToProjectSettings: reverted (0.0674s)

Related to #600051