Add skills code review agent example

[zzp1221]

概要

• 新增 skills_code_review_agent 示例，并保持与 quickstart 一致的目录结构。
• 实现基于 Skill 的自动代码评审流程，包含沙箱执行、Filter 治理、SQLite 持久化、敏感信息脱敏、finding 去重和结构化报
  告。
• 新增 8 条公开 diff 样例和验收测试，覆盖报告生成、数据库存储、沙箱失败、超时与输出限制、高风险脚本拦截、敏感信息脱敏
  等场景。

主要内容

• examples/skills_code_review_agent/run_agent.py
• examples/skills_code_review_agent/agent/
• examples/skills_code_review_agent/skills/code-review/
• examples/skills_code_review_agent/schema.sql
• examples/skills_code_review_agent/fixtures/
• examples/skills_code_review_agent/sample_outputs/
• tests/examples/test_skills_code_review_agent.py

测试

.venv\Scripts\python.exe -m pytest tests\examples\test_skills_code_review_agent.py
py -3.13 -m compileall examples\skills_code_review_agent tests\examples\test_skills_code_review_agent.py

结果：

- 15 passed
- compileall passed

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
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Additional details and impacted files

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