PP004 — removed

这篇还没有中文，下面是英文原文。

• Date: 2026-10-22 (Asia/Shanghai)
• Reason: jitter warm/purge ≈1.35×; re._cache invalidates hot-loop compile smell
• Policy: id retired permanently; do not renumber other rules to fill the gap; do not reuse PP004 for a new smell.