[User Session] Clear metadata on older sessions (#10751)

### Closes #10744

This pull request introduces a new background job to clear outdated user
session data and schedules it to run daily. The job ensures sensitive
session information is removed for sessions older than one year. Below
are the most important changes:

### Addition of a new job:

*
[`app/jobs/user/clear_old_user_sessions_job.rb`](diffhunk://#diff-19bd9b2978ef88bf9ae1db00fbb346141d92e5d85c4cb816b8949d814f0c4792R1-R21):
Added a new job `ClearOldUserSessionsJob` to the `User` namespace. This
job iterates through user sessions older than one year and clears
sensitive data such as `device_info`, `os_info`, `timezone`, `ip`, and
location details (`latitude` and `longitude`).

### Scheduling the job:

*
[`config/schedule.yml`](diffhunk://#diff-18c4a92c666266e8bead5b6ddb034501022877cdf773c0d337499ed0a7f6d341R175-R179):
Scheduled the new `ClearOldUserSessionsJob` to run daily at 3:00 AM with
a low priority queue.

[Internal
discussion](https://hackclub.slack.com/archives/C047Y01MHJQ/p1750259883680629)

---------

Co-authored-by: github-actions[bot] <41898282+github-actions[bot]@users.noreply.github.com>
Co-authored-by: Gary Tou <[email protected]>

Author: 3 people

app/jobs/user_session/clear_old_user_sessions_job.rb

@@ -0,0 +1,13 @@
+# frozen_string_literal: true
+
+class UserSession
+  class ClearOldUserSessionsJob < ApplicationJob
+    queue_as :low
+
+    def perform
+      UserSession.expired.where("created_at < ?", 1.year.ago).find_each(&:clear_metadata!)
+    end
+
+  end
+
+end

app/models/user_session.rb

@@ -81,6 +81,14 @@ def expired?
     expiration_at <= Time.now
   end
 
+  def clear_metadata!
+    update!(
+      device_info: nil,
+      latitude: nil,
+      longitude: nil,
+    )
+  end
+
   private
 
   def user_is_unlocked

config/schedule.yml

@@ -172,6 +172,11 @@ update_teenager_column_job:
   cron: "0 7 * * *" # run every 1 day
   class: "User::UpdateTeenagerColumnJob"
 
+clear_old_user_sessions:
+  cron: "0 3 * * *" # every day at 3:00 AM
+  class: "UserSession::ClearOldUserSessionsJob"
+  queue: low
+
 card_grant_expiration_job:
   cron: "0 7 * * *" # run every 1 day
   class: "CardGrant::ExpirationJob"