Slim routing strategy instead of middleware

Replace the Slim middleware with a routing strategy so the Route can stay intact.

https://www.slimframework.com/docs/v4/objects/routing.html#route-strategies

Start by locating the current Slim middleware and the Route implementation, then read the linked Slim routing strategies documentation. Replace the middleware approach with a routing strategy while keeping the Route intact; verify the existing controller behavior still works.

Written by the indexing model from the issue text.