Scan app/authz/<name>.{ts,js} the same way app/schemas is scanned,
exposing Router.authz: ComponentRef[]. Also update the two other
literal Router construction sites (prod runtime, dev-server test
fixture) that now need the new required field.
scanDir gains an optional extraExtensions parameter (default []) so
the authz scan can accept .js files without widening the extension
allow-list used by route scanning (app/pages, app/api, app/realtime),
which would otherwise leak .js into generated route URLs via
fileToRoute.
Clintchiz
e7743cdbb5