Add React frontend and clean up legacy HTTP backend

docker-compose.yaml

@@ -1,7 +1,18 @@
 services:
-  api:
+  backend:
     build: .
     ports:
       - "5000:5000"
     volumes:
-      - ./:/app
+      - ./:/app
+
+  frontend:
+    image: node:22-alpine
+    working_dir: /app
+    volumes:
+      - ./frontend:/app
+    ports:
+      - "5173:5173"
+    command: sh -c "npm install && npm run dev -- --host"
+    depends_on:
+      - backend