Inject session user_id into production logs

What does this MR do and why?

Enrich OpenTelemetry log records with structured request attributes (user_id, caller_id, params) so that log entries in SigNoz can be filtered and correlated to specific users, controllers, and actions.

Closes #536

Screenshots

Validation steps

1. Clone SigNoz and start it locally:

   git clone https://github.com/SigNoz/signoz.git
   cd signoz/deploy/docker
   docker compose up -d

2. Comment out the guard clause in contributors/config/initializers/opentelemetry.rb:

   # return unless Rails.env.production?

3. Start the Dev Container and make a request while logged in.
4. Open SigNoz at http://localhost:8080 and navigate to Logs.
5. Verify log records include structured user_id, caller_id, and params attributes.

/cc @leetickett-gitlab