Optimize validation for large datasets

**Feature request**
It would be great to have analytics for handlers.

**Use case**
Many users need this functionality for production deployments.

**Implementation idea**
Add a new config option `enable_analytics` with default `false`.

No files, tests, or entry points are named. First locate handler configuration and clarify what analytics should collect and expose; then trace the existing configuration flow. Done should include a default-disabled enable_analytics option, defined analytics behavior when enabled, and tests for both settings.

Written by the indexing model from the issue text.