feat: add new file

start.sh

@@ -0,0 +1,29 @@
+#!/usr/bin/env bash
+set -e
+
+# 项目根目录
+ROOT="$(cd "$(dirname "$0")" && pwd)"
+
+echo "== 检查 Node / npm =="
+if ! command -v node >/dev/null 2>&1 || ! command -v npm >/dev/null 2>&1; then
+  echo "未检测到 node 或 npm，请先安装 Node.js 再运行本脚本。"
+  exit 1
+fi
+
+echo "== 安装后端依赖 =="
+cd "$ROOT/backend"
+npm install
+
+echo "== 启动后端 (http://localhost:3000) =="
+npm run dev &
+BACKEND_PID=$!
+
+echo "== 安装前端依赖 =="
+cd "$ROOT/frontend"
+npm install
+
+echo "== 启动前端 (http://localhost:5173) =="
+npm run dev
+
+echo "== 结束前关闭后端 =="
+kill "$BACKEND_PID" 2>/dev/null || true