Refactor middleware for better readability

**Description**
Currently models lacks proper search support.

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

**Priority**: Low/Medium

Start by locating the middleware and model-handling entry points in the repository, then trace how search requests are currently processed. Clarify the intended configurable options and sensible defaults before changing behavior. Done means model search is configurable with agreed defaults and the middleware remains readable.

Written by the indexing model from the issue text.