Add TypeScript types for middleware

**Description**
Currently data lacks proper import support.

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

**Priority**: Low/Medium

Start by locating the middleware and the code handling data imports, then identify where TypeScript types belong. Check how imports are currently configured and what defaults exist. Done means middleware has usable TypeScript types and configurable imports with sensible defaults.

Written by the indexing model from the issue text.