Refactor JWT_SECRET handling in deploy.sh to use printf for consistent formatting. This change ensures that the JWT_SECRET is correctly appended to backend/.env with a newline, improving the script's reliability.

deploy.sh

@@ -70,14 +70,14 @@ cp .env.backend.example backend/.env
 if [ ! -f backend/.env ]; then
     echo -e "${BLUE}🔑 生成随机 JWT_SECRET...${NC}"
     JWT_SECRET=$(tr -dc A-Za-z0-9 </dev/urandom | head -c 48)
-    echo "JWT_SECRET=$JWT_SECRET" > backend/.env
+    printf "\nJWT_SECRET=$JWT_SECRET\n" > backend/.env
     echo -e "${GREEN}✅ 已生成 backend/.env 并写入 JWT_SECRET${NC}"
 else
     # 若已存在 .env，检查是否包含 JWT_SECRET，没有则添加
     if ! grep -q "^JWT_SECRET=" backend/.env; then
         echo -e "${BLUE}🔑 写入随机 JWT_SECRET 到已有 backend/.env...${NC}"
         JWT_SECRET=$(tr -dc A-Za-z0-9 </dev/urandom | head -c 48)
-        echo "JWT_SECRET=$JWT_SECRET" >> backend/.env
+        printf "\nJWT_SECRET=$JWT_SECRET\n" >> backend/.env
         echo -e "${GREEN}✅ 已写入随机 JWT_SECRET 到 backend/.env${NC}"
     else
         echo -e "${YELLOW}ℹ️ backend/.env 已存在 JWT_SECRET，跳过自动生成${NC}"