docs: document delegated plan review failure

packages/plan/plan-mode/README.i18n.yaml

@@ -2,5 +2,5 @@
 # side as of the last confirmed-consistent state. Both languages carry equal authority;
 # after editing either side, bring the other along and re-record with:
 #   pnpm run verify-translation-pairing --write packages/plan/plan-mode/README.md
-README.md: b22e218d1a0350d9dfb6e64fcaed426deaceb33e
-README.zh.md: 57ac85577a690d5c560bec39bef851692be03efd
+README.md: f2a78fe98b6a85ce91d727e95ddf62e6f77546b7
+README.zh.md: e1b5f111fd8f761fdd8f25558463c0cc327a14be

packages/plan/plan-mode/README.md

@@ -94,4 +94,5 @@ Mode transitions do not change the tool catalog; plan arguments and review resul
 - Plan mode guides rather than enforces; deployments needing a hard boundary must combine independent sandbox and approval controls.
 - A pending selection made while idle is lost if the process exits before the next boundary, so the UI must reapply it.
 - Forked agents inherit logged plan state, while newly spawned agents begin inactive; there is no creation-time plan option.
+- A live child owned by another agent cannot open the `exit_plan_mode` review. The failed call tells the child to include the unresolved decision in its final result; durable fork lineage alone does not prevent a session resumed as a runtime root from opening the review.
 - Only the Web UI has a specialized `plan-review` renderer; another interaction provider may present the same request through its generic option flow.

packages/plan/plan-mode/README.zh.md

@@ -94,4 +94,5 @@ mode 转换不改变工具目录；plan 参数与评审结果按常规方式扩
 - Plan mode 只进行引导，而不强制执行；需要硬边界的部署必须组合独立的沙箱与批准控制。
 - 如果进程在下一个边界之前退出，空闲时作出的待生效选择会丢失，因此 UI 必须重新应用它。
 - Fork 的 agent 会继承已记录的 plan 状态，新 spawn 的 agent 则从未激活状态开始；不存在创建时 plan 选项。
+- 由另一个 agent 所有的存活子级无法打开 `exit_plan_mode` 审阅。该调用失败时会提示子级在最终结果中包含尚未解决的决策；仅有持久化 fork 谱系并不会阻止恢复为运行时根的会话打开该审阅。
 - 只有 Web UI 具备专用的 `plan-review` 渲染器；其他交互提供方可以通过通用选项流程呈现同一请求。