Blank page is rendered on certain unavailable paths instead of a 404 #6260

Describe the bug

Navigating to a module's base path without an object ID — e.g. /items or /collections — renders a blank page instead of a proper 404 Page Not Found.

The cause is in the route configuration. In app-routes.ts, items and collections are valid top-level segments (they map via loadChildren to item-page-routes.ts and collection-page-routes.ts respectively). Once the router commits to one of these branches, it tries to match the remaining (empty) URL segment against the module's child routes. However, those child route arrays only define :id-based routes (and version / create), with no path: '' fallback and no ** wildcard. The empty segment matches nothing, so the router outlet has nothing to render — producing a blank page. Because top-level matching succeeded, the global { path: '**' } 404 route is never reached.

By contrast, /entities correctly returns a 404 because its route requires an :entity-type segment (entities/:entity-type), so it falls through to the global wildcard.

To Reproduce

Steps to reproduce the behavior:

In the browser, navigate directly to /items (or /collections).
Observe that a blank page is rendered.

Expected behavior

Navigating to a module base path without a valid object ID (e.g. /items, /collections) should render the 404 Page Not Found page (ideally redirecting to the dedicated error route so the URL reflects the error and SSR can return a proper 404 status), consistent with the behavior of /entities.

Related work

n/a