feat: 【日志平台】V4 分隔符与正则清洗支持 error_strategy --story=136788934

[yiqiwang-17]

Summary

• 统一 V4 JSON、分隔符、正则清洗的 drop/null 失败策略判定
• 为 split_str 预接入 error_strategy 和 min_parts，为 regex 预接入 error_strategy
• 补充开关真值表、最少列数计算测试及 V4 清洗快照

Dependency

🚧 当前 PR 仅用于预接入和评审，引擎依赖完成前禁止合并或部署。

• bkop 现网 V4 引擎实测会拒绝 regex.error_strategy，并忽略 split_str.error_strategy
• 需 Rust databus_runtime 先支持 split_str.min_parts/error_strategy 与 regex.error_strategy
• 发布顺序必须是：V4 清洗引擎 → bk-monitor
• 引擎就绪后再用 databus/clean/debug/ 验证缺列、正则不匹配的 drop/null 行为

Test plan

• python manage.py test apps.tests.log_databus -v 1 --noinput（360 passed）
• 引擎单测覆盖 split_str / regex 的 drop、null 与正常输入
• 引擎部署后执行 bkop clean debug 联调

TAPD

• 1010158081136788934

[codecov-commenter]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 61.05%. Comparing base (3068080) to head (5507a7d).
⚠️ Report is 6670 commits behind head on master.

Additional details and impacted files

@@            Coverage Diff             @@
##           master   #11929      +/-   ##
==========================================
+ Coverage   54.28%   61.05%   +6.77%     
==========================================
  Files         807      920     +113     
  Lines       45868    66584   +20716     
==========================================
+ Hits        24901    40656   +15755     
- Misses      20967    25928    +4961     

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