Trailing slashes for =HRRestRouter= (v2 / v3)

=HRRestRouter.register_view= normalizes non-empty routes to end with =/=

and registers one Django =path()= per view. It does not create duplicate

=*-noslash= route names.

ViewSets keep DRF =SimpleRouter= defaults (=trailing_slash="/"=).

Guardrail:

=app/tests/rest/test_urls.py::UrlsTestCase::test_view_routes_end_in_trailing_slash=

asserts that no registered v2 route name ends with =-noslash=.