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/plugins/urls.py

@@ -4,6 +4,6 @@ from . import views
 from .base import plugin_urlpatterns
 
 urlpatterns = [
-    path('plugins/', views.plugin_manifest, name='plugin-manifest'),
+    path('plugins/', views.PluginManifestView.as_view(), name='plugin-manifest'),
     *plugin_urlpatterns(),
 ]