Update validation documentation

**Description**
Currently lib lacks proper caching support.

**Proposed solution**
Add configurable caching with sensible defaults.

**Priority**: Low/Medium

Start by inspecting the lib directory and locating the validation-related code or documentation. Clarify whether the intended work is documentation or configurable caching, then identify the affected entry points and existing tests. Done means the requested validation documentation is updated or caching works with documented defaults and coverage.

Written by the indexing model from the issue text.