Update config documentation

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

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

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

The issue names no file, test, or entry point. First locate the configuration parsing and validation paths, then determine where validation analytics should be recorded and how the new option is documented. Done means enable_analytics defaults to false, the option controls the requested analytics behavior, and the relevant documentation and tests reflect it.

Written by the indexing model from the issue text.