fix(schedule): close review gaps

docs/subsystems/persistence.md

@@ -10,6 +10,8 @@ The seam is a textbook [capability seam](../../.agents/notes/implemented/archite
 
 `session/event` is a *synchronous* notification; persistence plugins copy the event into a per-session controller without blocking the producer. The first pending event starts a fixed batching window, and later events join without resetting its deadline. Expiry starts one durable batch; events admitted during that write receive their own deadline and form a follow-up batch. `session/flush` cancels the wait and drains through quiescence, so the loop still uses it as the ordering and error-observation checkpoint before claiming the next ordinary turn. A rejected background write retains its events and pauses automatic retry; a new event starts a fresh window, while explicit flush retries immediately and reports failure through `agent/error` and the logger, never as a session event past the closed turn. Disposal performs the same final drain. The configured maximum bounds only intentional batching wait, not event-loop scheduling or backend durability latency ([decision](../../.agents/notes/implemented/architecture/2026-08-08-bounded-session-persistence-write-batching.md)).
 
+A `session/flush` listener returns literal `true` only after completing durability work; observe-only listeners return void. Once every listener settles, `SessionStore.flush()` returns `true` and publishes contained `session/flushed(session, throughSeq)` only when at least one listener acknowledged durability and none failed. `throughSeq` is the exclusive event boundary captured at call entry, so events appended during the checkpoint require a later success; concurrent checkpoints may publish boundaries out of order. An empty or observe-only checkpoint returns `false`, and a rejection publishes no success observation.
+
 ## Crash recovery preserves an interrupted turn
 
 A backend that reloads a log crashed mid-turn finds an open `turn/start` with no `turn/end`. It does **not** truncate — a single turn can be huge in a long-horizon task (many steps, large tool output), and those events were durably appended before the crash. Instead it closes the orphaned turn with a synthetic `turn/end { reason: { kind: 'interrupted' } }`, keeping the interrupted execution balanced without changing any standalone events before or after it. `interrupted` is the one `TurnEndReason` no loop emits (see [session.md](session.md#why-a-turn-ended-turnendreasonmap)).

docs/subsystems/persistence.zh.md

@@ -10,6 +10,8 @@
 
 `session/event` 是一个*同步*通知；持久化插件会将事件复制到逐会话控制器，而不阻塞生产方。第一个待处理事件会开启固定批处理窗口，后续事件会加入但不会重置截止时间。窗口到期后会启动一个持久化批次；该次写入期间接纳的事件会获得自己的截止时间，并形成后续批次。`session/flush` 会取消等待并排空至完全停稳，因此循环仍将其用作在领取下一个普通轮次之前的顺序与错误观察检查点。后台写入被拒绝时会保留对应事件并暂停自动重试；新事件会开启新的固定窗口，而显式 flush 会立即重试，并通过 `agent/error` 和 logger 报告失败，绝不会把失败记录成已关闭轮次之后的会话事件。dispose（资源释放）会执行同样的最终排空。配置的最大值只限制有意的批处理等待，不限制事件循环调度或后端完成持久化的延迟（[决策](../../.agents/notes/implemented/architecture/2026-08-08-bounded-session-persistence-write-batching.md)）。
 
+`session/flush` 监听器只有在完成持久性工作后才返回字面量 `true`；仅观察监听器返回 void。每个监听器都结算后，仅当至少一个监听器确认持久性且没有监听器失败时，`SessionStore.flush()` 才返回 `true`，并以失败收容方式发布 `session/flushed(session, throughSeq)`。`throughSeq` 是调用入口捕获的事件排他边界，因此检查点期间追加的事件需要后续另一次成功；并发检查点可能不按顺序发布边界。空检查点或仅观察检查点返回 `false`，出现拒绝时不会发布成功观测。
+
 ## 崩溃恢复保留被中断的轮次
 
 后端重新加载一个在轮次中途崩溃的日志时，会发现一个已打开的 `turn/start` 却没有 `turn/end`。它**不会**截断日志：在长周期任务中，单个轮次可能非常庞大（许多步骤、大量工具输出），而这些事件在崩溃前已被持久追加。后端改为用一个合成的 `turn/end { reason: { kind: 'interrupted' } }` 关闭这个遗留轮次，在不改变其前后任何独立事件的情况下配平被中断的执行。`interrupted` 是唯一一个不由循环发出的 `TurnEndReason`（见 [session.md](session.md#why-a-turn-ended-turnendreasonmap)）。

docs/subsystems/subagent.md

@@ -156,7 +156,7 @@ type SubagentInterruptAuthority =
 
 Every Activation owns its `AgentHandle` and an `ownedChildren: Set<SessionId>`; because one Session has at most one live Activation, the child Session id identifies the live child without another runtime-incarnation reference. Starting a child or submitting parent-originated work registers the child in a continuation-managed parent's set before the child can run, and that parent cannot settle while the set is non-empty. A top-level or other non-continuation Agent has no Activation and stays outside the waiting graph. Child release happens only after the child Agent is quiescent, every child of that child is disposed, the best-effort final session flush settles, and the child's `AgentHandle` completes disposal.
 
-Final settlement awaits `ctx.sessions.flush(session)` but ignores its participation boolean because an arbitrary listener cannot prove that a persistence backend stored the state. Rejection is logged without failing the Activation, and the manager still disposes the handle and releases ownership; the persisted child state may then be missing or stale on a later resume. Manager unload invokes an internal manager-wide drain that closes admission and disposes every live forest; `drainContinuableDescendants(parents)` closes admission only below exact live host-owned Agents and disposes their continuable descendants while unrelated forests remain live. Both await already-admitted materializations in their scope, propagate cancellation top-down, release handles child-first, and await every selected branch despite individual failures. Durable child Sessions survive that process-local teardown.
+Final settlement awaits `ctx.sessions.flush(session)` but deliberately does not make its durability acknowledgement a release condition because continuation teardown is best effort. A `false` result still disposes the handle and releases ownership; rejection is logged without failing the Activation, and the persisted child state may then be missing or stale on a later resume. Manager unload invokes an internal manager-wide drain that closes admission and disposes every live forest; `drainContinuableDescendants(parents)` closes admission only below exact live host-owned Agents and disposes their continuable descendants while unrelated forests remain live. Both await already-admitted materializations in their scope, propagate cancellation top-down, release handles child-first, and await every selected branch despite individual failures. Durable child Sessions survive that process-local teardown.
 
 ```ts type-equiv
 /** Attribution for a model coordinator's follow-up to one of its children. */

docs/subsystems/subagent.zh.md

@@ -156,7 +156,7 @@ type SubagentInterruptAuthority =
 
 每个 Activation 都拥有自己的 `AgentHandle` 和一个 `ownedChildren: Set<SessionId>`；由于一份会话至多有一个存活 Activation，子会话 id 无需另一个运行时化身引用即可标识存活的子 agent。启动子 agent 或提交源自 parent 的工作，会在子 agent 能够运行之前将其注册到受继续执行管理的父级集合中；只要该集合非空，该父级就无法 settle。顶层或其他非继续执行的 Agent 没有 Activation，处于 waiting 图之外。只有当子 Agent 已完全停稳、该子 agent 的每个子级都已 dispose、best-effort 的最终会话 flush 结算完毕，且子 agent 的 `AgentHandle` 完成 dispose 之后，才会释放子 agent。
 
-最终结算会等待 `ctx.sessions.flush(session)`，但会忽略其参与布尔值，因为任意 listener 都无法证明某个持久化后端已存储该状态。rejection 会被记录，但不会使 Activation 失败；管理器仍会 dispose 该 handle 并释放所有权，此后持久化的子 agent 状态在后续恢复时可能缺失或陈旧。管理器卸载会调用内部的管理器全局 drain，关闭准入并 dispose 每片在线森林；`drainContinuableDescendants(parents)` 只关闭由 host 确切拥有的在线 Agent 之下的准入，并 dispose 其可继续后代，而无关森林保持在线。两者都会等待各自作用域内已获准的物化过程，自顶向下传播取消，按 child-first 顺序释放 handle，并且即使个别分支失败也会等待所有选中分支。持久化子会话不受该进程内拆卸的影响。
+最终结算会等待 `ctx.sessions.flush(session)`，但由于继续执行拆卸采用 best-effort，明确不把其持久性确认作为释放条件。结果为 `false` 时仍会 dispose 该 handle 并释放所有权；rejection 会被记录，但不会使 Activation 失败，此后持久化的子 agent 状态在后续恢复时可能缺失或陈旧。管理器卸载会调用内部的管理器全局 drain，关闭准入并 dispose 每片在线森林；`drainContinuableDescendants(parents)` 只关闭由 host 确切拥有的在线 Agent 之下的准入，并 dispose 其可继续后代，而无关森林保持在线。两者都会等待各自作用域内已获准的物化过程，自顶向下传播取消，按 child-first 顺序释放 handle，并且即使个别分支失败也会等待所有选中分支。持久化子会话不受该进程内拆卸的影响。
 
 ```ts type-equiv
 /** Attribution for a model coordinator's follow-up to one of its children. */