feat(leads): add Lead Manager module with full admin and consumer endpoints

- Lead model in admin_api with status/priority/source/assigned_to fields
- Admin API: metrics, list, detail, update views at /api/v1/leads/
- Consumer API: public ScheduleCallView at /api/leads/schedule-call/
- RBAC: 'leads' module registered in ALL_MODULES and StaffProfile scopes
- Migration 0003_lead with indexes on status, priority, created_at, email

mobile_api/urls.py

@@ -1,5 +1,6 @@
 from django.urls import path
 from .views import *
+from mobile_api.views.user import ScheduleCallView
 from mobile_api.views.reviews import ReviewSubmitView, MobileReviewListView, ReviewHelpfulView, ReviewFlagView
 from ad_control.views import ConsumerFeaturedEventsView, ConsumerTopEventsView
 
@@ -13,6 +14,7 @@ urlpatterns = [
     path('user/update-profile/', UpdateProfileView.as_view(), name='update_profile'),
     path('user/bulk-public-info/', BulkUserPublicInfoView.as_view(), name='bulk_public_info'),
     path('user/google-login/', GoogleLoginView.as_view(), name='google_login'),
+    path('leads/schedule-call/', ScheduleCallView.as_view(), name='schedule_call'),
 ]
 
 # Event URLS