refactor(agent-loop): rely on eager session persistence

.agents/notes/implemented/simplification/2026-07-17-one-send-one-turn.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
-2026-07-17-one-send-one-turn.md: 12055e9dcb6f59fb5a8f33a987717e37e20d9a1f
-2026-07-17-one-send-one-turn.zh.md: d57c10b127a0e9610957d9eb201ddd07eff64915
+2026-07-17-one-send-one-turn.md: 5d25d46a2d7a11be5761c49267b9f7e605035836
+2026-07-17-one-send-one-turn.zh.md: e223f5bcb93cdc7032f8b0ccf550322b9c98facf

.agents/notes/implemented/simplification/2026-07-17-one-send-one-turn.md

@@ -24,7 +24,7 @@ Prompt admission decides one message at a time. An allowed prompt becomes that t
 
 The no-batching rule applies only to ordinary `send()`. Running `steer()` puts input in the outbox. While a turn remains open, the loop records that input at the next step boundary and steering makes another step the default. A failure before that boundary leaves the steering staged without waking the agent; `retry()` or a later prompt takes it, while cancellation or disposal can discard it. When the agent is idle, `steer()` delegates to `send()`, so it creates an independent ordinary queue item.
 
-`inject()` continues to add model-facing context without submitting an ordinary message. During a turn it waits in the outbox for a safe step boundary; while idle it appends and flushes a `user/message` directly, without opening a turn or running the model. `whenIdle()` and disposal await that flush. `cancel()` remains a whole-agent operation that can clear all unstarted ordinary and steering input and abort the current step. `status` and `whenIdle()` also describe the whole agent, not one message. Several one-message turns can share one `running` interval, so `running` does not prove that a turn is open.
+`inject()` continues to add model-facing context without submitting an ordinary message. During a turn it waits in the outbox for a safe step boundary; while idle it appends a `user/message` directly, without opening a turn or running the model. Persistence owns the resulting eager drain. `cancel()` remains a whole-agent operation that can clear all unstarted ordinary and steering input and abort the current step. `status` and `whenIdle()` also describe the whole agent, not one message. Several one-message turns can share one `running` interval, so `running` does not prove that a turn is open.
 
 ## Alternatives considered
 

.agents/notes/implemented/simplification/2026-07-17-one-send-one-turn.zh.md

@@ -24,7 +24,7 @@ Status: implemented
 
 上述不合批规则只适用于普通 `send()`。agent 运行时，`steer()` 会把输入放入 outbox。只要当前轮次仍然打开，agent loop 就会在下一个步骤边界记录该输入，而 steering（中途引导）会默认让循环再执行一个步骤。在到达该边界前发生失败，会让 steering 保持暂存且不唤醒 agent；`retry()` 或后续提示词会取走它，而取消或 dispose 可以将其丢弃。agent 空闲时，`steer()` 委托给 `send()`，因此会创建一个独立的普通队列项。
 
-`inject()` 继续添加面向模型的上下文，而不提交普通消息。轮次打开时，该上下文会留在 outbox 中，等待安全的步骤边界；agent 空闲时，系统会直接追加一条 `user/message` 并完成持久化刷新，既不打开轮次，也不运行模型。`whenIdle()` 和 dispose 会等待该刷新完成。`cancel()` 仍是面向整个 agent 的操作，可以清空所有尚未启动的普通输入和 steering，并中止当前步骤。`status` 和 `whenIdle()` 描述的也是整个 agent，而不是某一条消息。多个单消息轮次可以共用一个 `running` 区间，因此 `running` 不表示轮次一定处于打开状态。
+`inject()` 继续添加面向模型的上下文，而不提交普通消息。轮次打开时，该上下文会留在 outbox 中，等待安全的步骤边界；agent 空闲时，系统会直接追加一条 `user/message`，既不打开轮次，也不运行模型。持久化层独立负责由此产生的即时排空。`cancel()` 仍是面向整个 agent 的操作，可以清空所有尚未启动的普通输入和 steering，并中止当前步骤。`status` 和 `whenIdle()` 描述的也是整个 agent，而不是某一条消息。多个单消息轮次可以共用一个 `running` 区间，因此 `running` 不表示轮次一定处于打开状态。
 
 ## 曾考虑的替代方案