Fix uri_for prefix behavior and ensure forward preserves app context;…

[Jkhall81]

Related Issue #1747

This PR fixes a bug where uri_for (and uri_for_route) did not respect the application prefix when called inside a forwarded request.

What’s fixed

• Forwarded requests now retain the app reference and uri_for_route callback.
• uri_for correctly applies the app prefix in both normal and forwarded requests.

Added

• New regression test: t/route_prefix_forward.t

This ensures that calling forward inside a prefixed app still generates proper prefixed URLs like /info/delete instead of /delete.