Add TypeScript types for store

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

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

**Priority**: Low/Medium

Start by locating the store and helpers entry points, then inspect how the project currently represents store types and performs searches. Confirm the desired configurable search behavior and sensible defaults from the surrounding implementation; done means the store has TypeScript types and search support that passes the relevant existing checks.

Written by the indexing model from the issue text.