docs(pm-dispatch): split a card that straddles an unreachable repository by repository (ruling D)

cross-repo-coordination.md lines 50-51 now carry the maintainer's
letter D: a card with a part in a repository its lane cannot reach is
split by repository at filing or first touch; that part is filed by a
reaching seat or parked here under domain:cloud + status:parked; this
card keeps only its own repository's work and does not read the other;
when it cannot be split, that repository's prerequisite card is filed
first; the dependent card goes pm:blocked + Blocked-by: owner/repo#N.
The old line 51 (unreachable target = reading gap) is replaced, and
the old line 50 (waiter flips pm:blocked + Blocked-by:) is folded into
the new line 51. Line-neutral at the file's 51-line ceiling.

Claude-Session: https://claude.ai/code/session_01HEdP5tPhqQfzwRmKDxwn85
Co-authored-by: Claude <noreply@anthropic.com>

Author: claude

.claude/skills/pm-dispatch/references/cross-repo-coordination.md

@@ -47,5 +47,5 @@
 - 转移落对方队列:目标仓立单带 `pm:queue`、出处行与一行可执行判据,依赖用 `Blocked-by:`。
 - 跨座位请求骑在它所关的既有卡上:请求席在自卡写 `Blocked-by:`,并在目标卡留一条评论。
 - 该评论点名席位与步骤;无既有卡承载且请求自身即立卡门 ①②④ 时才立新卡。
-- 等待方同一笔把自卡翻 `pm:blocked` + `Blocked-by:` 指向请求卡;⛔ 不设新标签新 sweep。
-- 目标仓不可达是读数缺口,不是落点:由可达席在目标仓立卡,此前请求记座位贴或协调卡。
+- 跨不可达仓的卡立卡或首触按仓拆:该仓部分由可达席立卡,或挂 `domain:cloud`+`status:parked`。
+- 本卡只留本仓活,不读他仓;拆不开先立该仓前置卡;依赖即 `pm:blocked`+`Blocked-by: owner/repo#N`。