♻️ Serve frontend from FastAPI (#2393)

Co-authored-by: github-actions[bot] <github-actions[bot]@users.noreply.github.com>

frontend/vite.config.ts

@@ -6,6 +6,10 @@ import { defineConfig } from "vite"
 
 // https://vitejs.dev/config/
 export default defineConfig({
+  build: {
+    outDir: "../backend/app/frontend",
+    emptyOutDir: true,
+  },
   resolve: {
     alias: {
       "@": path.resolve(__dirname, "./src"),