docs(pm-dispatch): add the witness-grep leg to the in-flight overlap interception

The in-flight overlap check asked one question — do the file faces
intersect — so a PR whose assertion NAMES a symbol another in-flight PR
deletes or renames passes both seats' checks and goes red only once both
land on one tree. Add a second leg: grep this round's deleted/renamed
identifiers against every in-flight PR's diff, not its file list, and
never skip it because the file faces are disjoint.

Paid at 241/241 by deleting one line in the same section whose rule
survives in SKILL.md (「⛔ 不在消费者侧打补丁」) and whose remainder was a
rationale tail for the copy-both-sentences rule stated one line above.

Claude-Session: https://claude.ai/code/session_01DAcomhvR9kKizeYgg89Vo8
Co-authored-by: Claude <noreply@anthropic.com>

Author: claude

.claude/skills/pm-dispatch/references/dispatch-runbook.md

@@ -210,14 +210,14 @@
 - ⛔ 仓内任何文件不得另立第三份,`check:skill-frame-sync` 全树扫;os-dev 定义没带就停下索取。
 - 文件面两句原文照抄:预期落点是 X。
 - 若实测表明真正的生产者在别包,直接按生产者侧修,落点与理由写进报告和 PR 正文。
-- ⛔ 不在消费者侧打补丁;只写一个路径名,是要求 dev 在守约与修对之间二选一。
 - 跨包常等于跨车道,PM 事后补跨座位声明。
 - 模型标识只禁内容工件:PR 标题与正文、代码注释、文档、changeset、评论。
 - 豁免不再申报为偏差:一是 harness 的 `Co-Authored-By` 尾注,免的是申报,trailer pair 仍 model-free。
 - 另一条是 `.claude/agents/*` frontmatter 的 `model:`,`check:agent-model-declared` 要求。
 - same-day churn 行:派发时 `git log origin/main --oneline -20 -- <paths>` 见当天合并即加一行。
 - 该行原文:基于合并后的代码工作,issue 引用的片段可能已变,先核对当前 main。
 - 在飞重叠每轮拦截:main 新落 PR 与在飞申报文件面求交,相交即发四句警告。
+- 另一腿:本轮删/改名标识符 grep 每个在飞 PR 的 diff,命中同发,⛔ 不因文件面不相交跳过。
 - 四句:合 main 重跑测试矩阵、读对方 diff 重划边界、只补它没覆盖的、被完全覆盖就停下。
 - ⛔ 不硬造 diff。中途收窄标准条款须点名替换承接人与时点,缺一 dev 报 blocked 不半执行。
 - 全仓 pin 清扫两句原文:① grep 错误码与错误消息全仓扫同语义 pin,一轮翻完,不只改本包。