fix(web): harden multimodal draft and storage lifecycle

packages/host/apiproxy/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/host/apiproxy/README.md
-README.md: 09f0f53bec81dd559c8da9c94a6b5459019b4ba2
-README.zh.md: bba5efaa0d9c9486b7367a6c8db069d10b18ffb5
+README.md: 5367795aeb7655f9323ab94d71803049ee452cb0
+README.zh.md: c1507f9c25595d83a63326127779c6240f9cc8a7

packages/host/apiproxy/README.md

@@ -20,7 +20,7 @@ Session titles ride the generic projection pair like every other domain — the
 
 Session model routing is a session-domain contract. `session.models` returns the selected provider/model/reasoning target with provider-grouped advisory models, exact-route reasoning metadata, and provider-local lookup failures. `session.selectModel` validates the optional adapter-owned reasoning effort and replaces the complete target selected for the next prompt-assembly boundary. Selection is serialized with image-bearing prompt admission and rejects a text-only target while an image is pending publication or remains in the current derived history; an image removed by compaction no longer blocks selection. Catalog membership is not validation: an adapter may resolve an unlisted model, while an unavailable route or unsupported effort returns `model-unavailable`.
 
-Pending queued input is a live control-plane contract, not session history. The gateway mirrors queued `InboxItem` occurrences from `agent/inbox/*` and broadcasts authoritative `session/queue` snapshots on every queued change and reconnect; pending steering stays outside this Web projection. `session.updateQueue` addresses one `InboxItemId`: edit replaces pending content and remove discards it. A driver claim wins races by retiring the address before admission; a later operation returns `queue-item-not-found`. The operation queries only an attached Agent and never resumes a cold session because process-local inbox identities do not survive restart or disposal. The client never infers retirement from turn or status events.
+Pending queued input is a live control-plane contract, not session history. The gateway mirrors queued `InboxItem` occurrences from `agent/inbox/*` and broadcasts authoritative `session/queue` snapshots on every queued change and reconnect; pending steering stays outside this Web projection. Image-bearing carriers separately gate text-only model selection until publication or discard: idle without publication retires a claimed queued carrier, but steering retained in the agent outbox remains gated across a failed turn. `session.updateQueue` addresses one `InboxItemId`: edit replaces pending content and remove discards it. A driver claim wins races by retiring the address before admission; a later operation returns `queue-item-not-found`. The operation queries only an attached Agent and never resumes a cold session because process-local inbox identities do not survive restart or disposal. The client never infers retirement from turn or status events.
 
 Workspace and Session lists are separate reconnect baselines. `workspace.create` creates a unique name or adopts an existing directory, `workspace.delete` removes only the Workspace registration, `session.create` accepts an optional preallocated Session id, and `host/workspace-changed`, `host/workspace-removed`, plus `host/session-added` carry committed increments in either arrival order. `workspace.archiveSession` adds one session to the registry-global archive set and answers the full updated set; `workspace.list` carries that set as the reconnect baseline and `host/archived-sessions-changed` pushes the full snapshot after every durable change. Archiving hides the session from grouping surfaces without touching its log or its workspace account; a session neither live nor persisted fails with `session-not-found`. Registration deletion preserves the directory and session logs; its Sessions remain in `session.list` and become Ungrouped. `SessionSummary.blank` and the `host/session-added` frame carry the derived zero-events bit: clients hide blank sessions and reuse them per workspace, flip blank on the first `host/session-status(running:true)`, and treat `session.list` as the reconnect authority; cold summaries are never blank because lazy persistence keeps never-appended sessions out of `list()`.
 

packages/host/apiproxy/README.zh.md

@@ -20,7 +20,7 @@
 
 会话模型路由属于会话领域契约。`session.models` 返回选中的提供方／模型／推理目标，以及按提供方分组的建议性模型、精确路由推理元数据和逐提供方查询失败记录。`session.selectModel` 校验由适配器持有的可选推理强度，并替换将在下一提示词组装边界使用的完整目标。模型选择与包含图片的提示词准入串行执行；当图片正等待发布或仍存在于当前派生历史中时，会拒绝选择纯文本目标；被压缩（compaction）移除的图片不再阻止选择。目录成员关系不构成校验：适配器可以解析未列出的模型，而不可用路由或不受支持的推理强度会返回 `model-unavailable`。
 
-待处理的 queued 输入属于实时控制平面契约，而非会话历史。网关镜像来自 `agent/inbox/*` 的 queued `InboxItem` 入队项，并在每次 queued 变更和重连时广播权威的 `session/queue` 快照；待处理 steering（中途引导）不进入此 Web 投影。`session.updateQueue` 通过 `InboxItemId` 寻址单个项：编辑会替换待处理内容，移除会将其丢弃。驱动器在接纳前退役寻址标识，因此认领会赢得竞态；之后的操作返回 `queue-item-not-found`。该操作只查询当前已挂载的 Agent，绝不恢复冷会话，因为进程本地 inbox 标识无法在重启或资源释放后存活。客户端绝不根据轮次或状态事件推断项已退役。
+待处理的 queued 输入属于实时控制平面契约，而非会话历史。网关镜像来自 `agent/inbox/*` 的 queued `InboxItem` 入队项，并在每次 queued 变更和重连时广播权威的 `session/queue` 快照；待处理 steering（中途引导）不进入此 Web 投影。含图片的载体会另行约束纯文本模型选择，直到发布或丢弃：未发布即转入空闲时，已认领的 queued 载体会被退役；但保留在 agent outbox 中的 steering 即使跨越失败轮次也仍受门槛约束。`session.updateQueue` 通过 `InboxItemId` 寻址单个项：编辑会替换待处理内容，移除会将其丢弃。驱动器在接纳前退役寻址标识，因此认领会赢得竞态；之后的操作返回 `queue-item-not-found`。该操作只查询当前已挂载的 Agent，绝不恢复冷会话，因为进程本地 inbox 标识无法在重启或资源释放后存活。客户端绝不根据轮次或状态事件推断项已退役。
 
 Workspace 列表与 Session 列表是相互独立的重连基线。`workspace.create` 会创建唯一名称或接纳现有目录，`workspace.delete` 只移除 Workspace 注册记录，`session.create` 接受可选的预分配 Session id，`host/workspace-changed`、`host/workspace-removed` 与 `host/session-added` 则以任意到达顺序携带已提交的增量。`workspace.archiveSession` 向注册表级全局归档集合添加一个会话，并应答完整的更新后集合；`workspace.list` 携带该集合作为重连基线，`host/archived-sessions-changed` 在每次持久变更后推送完整快照。归档只把会话从各分组视图中隐藏，不触碰其日志和 workspace 记账；既非实时也未持久化的会话以 `session-not-found` 失败。删除注册记录会保留目录和会话日志；相关 Session 仍留在 `session.list` 中，并进入 Ungrouped。`SessionSummary.blank` 与 `host/session-added` 帧携带派生的零事件位：客户端隐藏空白会话并按 workspace 复用它们，在首个 `host/session-status(running:true)` 时翻转 blank，并以 `session.list` 作为重连权威；冷会话摘要永远不是空白：惰性持久化让从未追加过事件的会话根本不出现在 `list()` 中。
 

packages/host/apiproxy/src/api-proxy.ts

@@ -877,9 +877,15 @@ export function createApiProxy(ctx: Context, defaults: ApiProxyDefaults): ApiPro
         if (changed) publishQueue(agent.id)
       }),
       ctx.on('agent/status', (agent: Agent, status: AgentStatus) => {
-        // Idle proves every claimed admission either published (retired by its
-        // session event) or ended without one; drop the stale gate carriers.
-        if (status === 'idle') pendingPublication.delete(agent.id)
+        if (status !== 'idle') return
+        const pending = pendingPublication.get(agent.id)
+        if (pending === undefined) return
+        // A claimed queued prompt disappears when admission ends without
+        // publication. Steering instead remains staged in the agent outbox
+        // across a failed turn, so retain it until steering/message or discard.
+        const kept = pending.filter(item => item.placement === 'steering')
+        if (kept.length === 0) pendingPublication.delete(agent.id)
+        else pendingPublication.set(agent.id, kept)
       }),
       ctx.on('session/disposed', (session: Session) => {
         queuedMirror.delete(session.id)

packages/host/apiproxy/tests/api-proxy-models.spec.ts

@@ -404,6 +404,11 @@ describe('Web session model selection', () => {
     ctx.emit('agent/inbox/dequeue', agent, steeringItem)
     expect((await api.sessions.selectModel(request({ sessionId, provider: 'text-only', model: 'plain' }))).result.ok).toBe(false)
 
+    // A failed turn returns idle while leaving steering staged in the outbox;
+    // only publication or discard may retire this carrier.
+    ctx.emit('agent/status', agent, 'idle')
+    expect((await api.sessions.selectModel(request({ sessionId, provider: 'text-only', model: 'plain' }))).result.ok).toBe(false)
+
     // Publication hands the gate over to the durable surface.
     agent.session.append('steering/message', { turn: 1, message: steering }, { surfaceOp: 'append' })
     expect((await api.sessions.selectModel(request({ sessionId, provider: 'text-only', model: 'plain' }))).result.ok).toBe(false)