chore(build): 更新预安装脚本配置

- 添加了 bash shebang 行
- 修改 pip 安装命令以使用腾讯云镜像源
- 保持虚拟环境创建和依赖安装流程不变
- 维持 playwright 浏览器安装步骤

pre_install.sh

@@ -1,6 +1,7 @@
+#!/bin/bash
 apt install -y python3.12-dev python3.12-venv
 python3 -m venv .venv --system-site-packages
 source .venv/bin/activate
-.venv/bin/python3.12 -m pip install -r requirements.txt
+.venv/bin/pip install -r requirements.txt -i https://mirrors.cloud.tencent.com/pypi/simple/
 .venv/bin/playwright install chromium
 .venv/bin/playwright install-deps chromium