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/manage.py

@@ -0,0 +1,22 @@
+#!/usr/bin/env python
+"""Django's command-line utility for administrative tasks."""
+import os
+import sys
+
+
+def main():
+    """Run administrative tasks."""
+    os.environ.setdefault('DJANGO_SETTINGS_MODULE', 'poker_api.settings')
+    try:
+        from django.core.management import execute_from_command_line
+    except ImportError as exc:
+        raise ImportError(
+            "Couldn't import Django. Are you sure it's installed and "
+            "available on your PYTHONPATH environment variable? Did you "
+            "forget to activate a virtual environment?"
+        ) from exc
+    execute_from_command_line(sys.argv)
+
+
+if __name__ == '__main__':
+    main()