docs(pm-skill): anchor recorded replays to surviving commits, and to content over positions (#14045)

The record-discipline block asks for reproductions on cards and rulings but
says nothing about what those records are pinned TO, and both pins expire
silently. A repro block stated at its own PR head goes unreplayable the moment
the branch is squash-merged and deleted: measured, one card's own block had two
of its three shas unresolvable, both PR-branch commits, while the surviving one
was the main-side diff base. The same shape reaches positions — one triage
round hit three dead line-number citations, every one relocated only via a
symptom string. The block reads replayable in both cases, and there is no
signal at write time.

One bullet, two legs: state a replay against a commit that survives (the main
merge commit, or base plus PR number) and never a PR head, saying so and
recording the inputs themselves — the diff, or the changed hunks — where the PR
head genuinely is the subject; and anchor content rather than positions, since
line numbers drift as files grow.

No gate: scanning card bodies for sha liveness would false-positive on every
unmerged PR, which is the card's own restraint and triage's concurrence.

Claude-Session: https://claude.ai/code/session_01Msg17tAHJ3jVTYFgHydCm2

Co-authored-by: Claude <noreply@anthropic.com>

Author: claude[bot]

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

@@ -119,6 +119,11 @@ fire 附带一次:
   同文件里确定存在、且 ⛔ 绝不是被测词子串的一个词;对照未通过的零记「没读到」,
   ⛔ 不记「不存在」(对照不要求作者预知自己会犯哪一类错);
   ② **锚点取最短的不折行片段**,⛔ 不抄脑中那整句。
+- **记录锚在活得下来的对象上**(实测:一卡的复现块三 sha 死二,皆 PR 分支;同轮三处行号引
+  用全失效,靠症状串重定位):① 重放按**能存活的 commit** 陈述 —— `main` 的合并 commit,或
+  base + PR 号,⛔ 永不用 PR head:分支一删 object 即不可达,而块读着仍可重放;PR head 确是主体时
+  明说,并把**输入本身**(diff 或改动 hunk)记在旁边,使运行无该 object 也可重建;② 同理**锚内
+  容、不锚位置** —— 行号随文件生长而漂,取症状字符串或独特标识符。
 - **行文纪律**:
   出处一行(日期 + 原话);实测叙事至多压成一行 —— 故事住在卡上,不进操作文本。