Implement Django backend and Vue frontend structure

- Django backend with projects, templates, exports apps
- SQLite database models for Project, Asset, CardLayer
- REST API endpoints for project management
- Vue frontend with Vite, Element Plus, Fabric.js
- Home page for project selection
- Editor page with Fabric.js canvas integration

backend/apps/projects/urls.py

@@ -0,0 +1,7 @@
+from django.urls import path
+from .views import project_list, project_detail
+
+urlpatterns = [
+    path('', project_list, name='project-list'),
+    path('<str:pk>/', project_detail, name='project-detail'),
+]