docs(policy): describe constructor-seeded inheritance

The implementation no longer stores inherited policy in SessionHeader or resolves a second baseline chain, but the feature, sandbox, and approval notes still described that machinery. Keeping those claims would make the smaller design look incomplete and invite reintroduction of the generic persistence surface.

Rewrite the owning feature note around the actual delegation snapshot: source-tagged policy events follow the optional fork prefix, ordinary last-event-wins folds establish precedence, and persistence captures the constructor seed with the first materialized batch. Condense the alternatives and consequences to the decisions and coverage that remain load-bearing.

Align the sandbox and approval notes plus the subagent-inprocess consumer README with that contract. Update the four Chinese counterparts minimally and re-record each pairing hash so both languages describe the same shipped mechanism.

packages/subagent/subagent-inprocess/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/subagent/subagent-inprocess/README.md
-README.md: 3606799e6d16e80473006f82b834a10953270914
-README.zh.md: 7f52d3699d1240f960e437d12bc48a152658cd15
+README.md: 02d9bd7d2dc792055a13d51402572313855ff1ff
+README.zh.md: f55467b37a948ef5a0a34bd45d8a11d7a004ff29

packages/subagent/subagent-inprocess/README.md

@@ -18,6 +18,8 @@ The driver follows this sequence:
 
 The child gets the parent's working-directory/session lineage and inherits the parent provider, model, and output-token cap unless `request.agentOptions` overrides them. It gets a fresh flat registration scope: parent ownership does not import parent tool restrictions or establish an authority subset.
 
+When the optional sandbox-policy or approval service is composed, the driver snapshots the parent's explicit session override before child creation and seeds a source-tagged event after any fork prefix. It never copies deployment defaults or one-shot grants; later child switches still win. See the [policy-inheritance decision](../../../.agents/notes/implemented/feature/2026-07-25-subagent-policy-inheritance.md).
+
 ## Cancellation and ownership
 
 The required request signal covers both startup and the live run. Before publication, `AgentCreationTransaction` observes it, rolls back, and rejects. The factory detaches that creation-only listener before returning; the driver immediately checks the signal once more before installing a minimal live-run listener, closing the handoff race. After publication, abort cancels the child.

packages/subagent/subagent-inprocess/README.zh.md

@@ -18,6 +18,8 @@
 
 子 agent 会获得父 agent 的工作目录／会话谱系；除非 `request.agentOptions` 覆盖，否则还会继承父 agent 的提供方、模型和输出 token 上限。它获得全新的扁平注册作用域：父级所有权不会导入父 agent 的工具限制，也不会建立权限子集。
 
+当组合中挂载了可选的沙箱策略或审批服务时，驱动器会在创建子 agent 前对父级的显式会话覆盖项获取快照，并在任意 fork 前缀之后预置一条带来源标记的事件。它绝不复制部署默认值或一次性授权；子 agent 后续的切换仍然优先。参见[策略继承决策](../../../.agents/notes/implemented/feature/2026-07-25-subagent-policy-inheritance.md)。
+
 ## 取消与所有权
 
 必需的请求信号同时覆盖启动阶段和实时运行。发布前，`AgentCreationTransaction` 会观察该信号、回滚并拒绝。工厂返回前会移除仅用于创建阶段的监听器；驱动器随即再次检查信号，然后安装最小化的实时运行监听器，从而消除交接竞态。发布后，中止会取消子 agent。