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

frontend/src/main.js

@@ -0,0 +1,12 @@
+import { createApp } from 'vue'
+import { createPinia } from 'pinia'
+import ElementPlus from 'element-plus'
+import 'element-plus/dist/index.css'
+import App from './App.vue'
+import router from './router'
+
+const app = createApp(App)
+app.use(createPinia())
+app.use(router)
+app.use(ElementPlus)
+app.mount('#app')