Optimize handlers for large datasets

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

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

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

Start by locating the configuration handling and the validation/search entry points in the repository. Trace how configuration defaults are loaded, then define completion as supporting the new enable_search option with a default of false and confirming search for validation works without changing existing behavior.

Written by the indexing model from the issue text.