feat: add public profiles list endpoint with search and pagination

- Add new /profiles/ endpoint for listing user profiles
- Support search by username/display name with ordering options
- Include pagination with configurable page size (max 100)
- Add comprehensive OpenAPI schema documentation
- Refactor passkey authentication state management in MFA flow
- Update URL routing and imports for new list_profiles view

This enables user discovery, leaderboards, and friend-finding features
with a publicly accessible, well-documented API endpoint.

backend/apps/api/v1/accounts/urls.py

@@ -6,6 +6,7 @@ from django.urls import include, path
 from rest_framework.routers import DefaultRouter
 
 from . import views, views_credits, views_magic_link
+from .views import list_profiles
 
 # Register ViewSets
 router = DefaultRouter()
@@ -119,7 +120,8 @@ urlpatterns = [
     # Magic Link (Login by Code) endpoints
     path("magic-link/request/", views_magic_link.request_magic_link, name="request_magic_link"),
     path("magic-link/verify/", views_magic_link.verify_magic_link, name="verify_magic_link"),
-    # Public Profile
+    # Public Profiles - List and Detail
+    path("profiles/", list_profiles, name="list_profiles"),
     path("profiles/<str:username>/", views.get_public_user_profile, name="get_public_user_profile"),
     # Bulk lookup endpoints
     path("profiles/bulk/", views.bulk_get_profiles, name="bulk_get_profiles"),