Complete identity smoke path: id_token claims, registration entry, cutover docs

Prefer verified KeyCape id_token claims when /userinfo returns 401; soft-fail
userinfo. Add CSOC-WP-0003 registration entry (disabled until NetKingdom URL),
AAL step-up hooks, smoke/cutover evidence for tegwick OIDC without MFA.

coulomb_social/apps/identity/urls.py

@@ -6,6 +6,7 @@ app_name = "identity"
 
 urlpatterns = [
     path("login/", views.login_start, name="login"),
+    path("register/", views.registration_start, name="register"),
     path("callback/", views.oidc_callback, name="callback"),
     path("logout/", views.logout_view, name="logout"),
     path("dev-login/", views.dev_login, name="dev_login"),