Add JWT auth with per-user data isolation and account settings.

Users can register, log in, and manage profile/password in a personal account page; server data is scoped by owner across contacts, maps, tags, and import.

Co-authored-by: Cursor <cursoragent@cursor.com>

backend/graph/urls.py

@@ -3,6 +3,6 @@ from django.urls import path
 from . import views
 
 urlpatterns = [
-    path('graph/', views.graph_data, name='graph-data'),
-    path('network-map-graph/', views.network_map_graph, name='network-map-graph'),
+    path('graph/', views.GraphDataView.as_view(), name='graph-data'),
+    path('network-map-graph/', views.NetworkMapGraphView.as_view(), name='network-map-graph'),
 ]