ci: add pull request validation workflow

[mason0510]

Summary

• add a GitHub Actions workflow that runs syntax validation for key Python scripts on pull requests
• add a minimal config schema smoke check so PRs do not silently break required runtime keys
• document the repo-level and GitHub-settings split for automatic PR review, including branch protection / rulesets and Copilot review boundaries

Test Plan

• ruby -e 'require "yaml"; YAML.load_file(".github/workflows/pr-check.yml"); puts "workflow yaml ok"'
• python3 -m py_compile OutlookRegister.py OutlookRegister_patchright.py get_token.py
• python3 - <<'PY' import json from pathlib import Path required_keys = { 'browser_path','proxy','Bot_protection_wait','max_captcha_retries','concurrent_flows','max_tasks','enable_oauth2','client_id','redirect_url','Scopes' } config = json.loads(Path('config.json').read_text(encoding='utf-8')) missing = sorted(required_keys - set(config)) assert not missing, f'config.json 缺少关键字段: {missing}' print('config.json schema smoke ok') PY

[mason0510]

Code review 结论：

• 范围清晰，只涉及 workflow / ignore / 文档
• 本地已验证 YAML 解析、py_compile、config.json 关键字段烟雾检查
• 当前未发现阻塞合并的问题
• 备注：真正拦截 merge 仍需仓库设置里开启 required status checks