fix(web): harden multimodal draft and storage lifecycle

.agents/notes/implemented/feature/2026-07-22-web-multimodal-image-input-and-durable-attachments.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 .agents/notes/implemented/feature/2026-07-22-web-multimodal-image-input-and-durable-attachments.md
-2026-07-22-web-multimodal-image-input-and-durable-attachments.md: 1b0e9083e205bb69f8a3ee9e4c073af7864b6ed7
-2026-07-22-web-multimodal-image-input-and-durable-attachments.zh.md: 095420b09ea34e98002480a218f74bc9f8421876
+2026-07-22-web-multimodal-image-input-and-durable-attachments.md: 6a0b109d4151207f89d38125eda2535c73e43057
+2026-07-22-web-multimodal-image-input-and-durable-attachments.zh.md: 4a3917ea2dae5252b4512c7fa707ef20cca8a7fd

.agents/notes/implemented/feature/2026-07-22-web-multimodal-image-input-and-durable-attachments.md

@@ -67,9 +67,9 @@ interface ComposerAttachment {
 }
 ```
 
-This split uses the session provide channel's input hook and actions as the single subscription path for live composer state while keeping non-serializable browser objects out of persisted JSON. Only the plain-text draft mirror uses `localStorage`; attachment identifiers, browser `File` objects, and object URLs remain scoped to the live session input shell. Unsent images therefore do not survive reload or session-scope disposal. A native client may stage input in an OS temporary directory, but it must treat that path exactly like the browser object URL: delete it when no longer needed and copy the bytes into the durable store before message acceptance.
+This split uses the session provide channel's input hook and actions as the single subscription path for live composer state while keeping non-serializable browser objects out of persisted JSON. Only the plain-text draft mirror uses `localStorage`; attachment identifiers, browser `File` objects, and object URLs remain scoped to the live session input shell. Unsent images therefore do not survive reload or session-scope disposal. A Workspace switch moves a mixed text-and-image draft only when the destination shell accepts the complete image batch; refusal leaves both parts with the source. A native client may stage input in an OS temporary directory, but it must treat that path exactly like the browser object URL: delete it when no longer needed and copy the bytes into the durable store before message acceptance.
 
-The local attachment backend resolves an explicit `dshHome`, then `$DSH_HOME`, then `~/.dsh`. It stores content-addressed objects below `$DSH_HOME/attachments/v1/objects/<prefix>/<sha256>` with owner-only directory and file permissions. A temporary file is written, synchronized, atomically published, and made durable with a directory sync on the publication directories (POSIX; Windows relies on filesystem metadata journaling) before the service returns a reference. The content digest is encoded in the opaque `sha256:<digest>` identifier. Admission and reads fully decode supported rasters before accepting their format and dimensions, and every read also verifies the digest, byte length, and logged metadata.
+The local attachment backend resolves an explicit `dshHome`, then `$DSH_HOME`, then `~/.dsh`. It stores content-addressed objects below `$DSH_HOME/attachments/v1/objects/<prefix>/<sha256>` with owner-only directory and file permissions. On each process's first save for one home, it creates that home and synchronizes every ancestor entry to the filesystem root; existence is not treated as durability because another process may still be between `mkdir` and parent `fsync`. A temporary file is then written, synchronized, atomically published, and made durable with directory syncs on the publication path (POSIX; Windows relies on filesystem metadata journaling) before the service returns a reference. The content digest is encoded in the opaque `sha256:<digest>` identifier. Admission and reads fully decode supported rasters before accepting their format and dimensions, and every read also verifies the digest, byte length, and logged metadata.
 
 The store performs no automatic deletion in version one. Sent user images and model-generated images remain reachable for history, resume, and fork. Reference-aware garbage collection needs a separate design because an age-only rule can delete data still referenced by a durable session. Deployment byte and pixel limits are admission policy on writes; reads verify the digest and recorded metadata without reapplying current admission limits, so lowering policy does not invalidate older history.
 
@@ -122,7 +122,7 @@ Base64 crosses JSON-RPC once and is discarded after persistence. The host valida
 
 Model catalog entries gain optional merge-extensible input modality declarations. A missing declaration means unknown; a present list without `image` is an explicit negative capability.
 
-The host is the authoritative preflight boundary. It resolves the session's latest routed provider/model, falling back through agent options to host defaults; if that model explicitly excludes image input, it rejects the prompt before writing any attachment or event, and the client restores the draft. Image-bearing prompt admission and model selection share one per-agent serial boundary, and a dequeued prompt remains pending until its durable message event publishes ([ordering decision](../bug-fix/2026-07-29-atomic-web-image-admission.md)); a steering carrier gates from its enqueue until its `steering/message` event publishes, closing the outbox hop that never enters the queued mirror. Selection rejects a text-only target while an image is pending publication or remains in the session's current derived history; compaction can remove old images and make a later text-only selection valid, and an admission that ends idle without publication releases the gate. `session.updateQueue` edits accept text content only, so a queue edit cannot inject an image past this admission boundary. Unknown capability proceeds to the adapter guard so uncatalogued model identifiers remain usable. The browser rejects unsupported declared image media types before allocating preview URLs, but it does not snapshot deployment limits or model capability: a handshake snapshot cannot represent a session's current target after `session.selectModel`, and deployment policy may change independently. The host validates the complete batch against current byte, count, aggregate, media, dimension, pixel, and routed-model policy before writing any attachment or event; its rejection renders through the composer error strip.
+The host is the authoritative preflight boundary. It resolves the session's latest routed provider/model, falling back through agent options to host defaults; if that model explicitly excludes image input, it rejects the prompt before writing any attachment or event, and the client restores the draft. Image-bearing prompt admission and model selection share one per-agent serial boundary, and a dequeued prompt remains pending until its durable message event publishes ([ordering decision](../bug-fix/2026-07-29-atomic-web-image-admission.md)); a steering carrier gates from its enqueue until its `steering/message` event publishes, closing the outbox hop that never enters the queued mirror. Selection rejects a text-only target while an image is pending publication or remains in the session's current derived history. Compaction can remove old images and make a later text-only selection valid; idle without publication releases a claimed queued carrier, while steering retained in the outbox stays gated until publication or discard. `session.updateQueue` edits accept text content only, so a queue edit cannot inject an image past this admission boundary. Unknown capability proceeds to the adapter guard so uncatalogued model identifiers remain usable. The browser rejects unsupported declared image media types before allocating preview URLs, but it does not snapshot deployment limits or model capability: a handshake snapshot cannot represent a session's current target after `session.selectModel`, and deployment policy may change independently. The host validates the complete batch against current byte, count, aggregate, media, dimension, pixel, and routed-model policy before writing any attachment or event; its rejection renders through the composer error strip.
 
 The Pi-AI adapter is the first visual-input route: it resolves `ctx.attachments` at request time, recursively converts each durable image reference including references nested inside tool results, and emits native image content only for models that declare image input. The shipped composition registers Pi-AI OpenAI and Anthropic routes alongside the text-only default DeepSeek route; selecting the active provider/model remains a host composition or profile concern rather than an image-input CLI feature. Request-time service resolution keeps Cordis load order from freezing optional attachment availability. The hand-written DeepSeek adapter throws typed `UNSUPPORTED_CONTENT` for an image anywhere in the request, including nested tool results. No adapter may flatten or skip an image.
 
@@ -140,7 +140,7 @@ Composer thumbnails and each `MessageImage` own ephemeral original-preview state
 
 ### Limits and trust boundaries
 
-Version one accepts PNG, JPEG, WebP, and GIF only. SVG and remote URLs are excluded. Default limits are 5 MiB per image, 10 images and 20 MiB aggregate image bytes per message, and 40 million intrinsic pixels per image. These deployment-varying limits are validated backend configuration and enforced by the host before persistence. The client connection carrier independently caps buffered API request bodies, deriving the cap from the host attachment service's aggregate image limit plus base64 and envelope expansion; a body without a declared length is rejected the moment it crosses the cap rather than drained to its end.
+Version one accepts PNG, JPEG, WebP, and GIF only. SVG and remote URLs are excluded. Default limits are 5 MiB per image, 10 images and 20 MiB aggregate image bytes per message, and 40 million intrinsic pixels per image. These deployment-varying limits are validated backend configuration and enforced by the host before persistence. The client connection carrier has an independent configurable `maxRequestBodyBytes` cap (32 MiB by default) for every API request and fails load if it cannot hold the attachment service's aggregate image limit after base64 and envelope expansion; lowering image policy therefore never silently lowers the carrier limit for valid text or other RPCs. A body without a declared length is rejected the moment it crosses the cap rather than drained to its end.
 
 Malformed base64, unsupported or mismatched media, truncated image payloads, excess bytes, excess image count, excess pixels, missing objects, and integrity mismatches return stable structured failures. Original filenames are reduced to a display basename, control characters are removed, and no local path is logged or returned to the browser.
 

.agents/notes/implemented/feature/2026-07-22-web-multimodal-image-input-and-durable-attachments.zh.md

@@ -67,9 +67,9 @@ interface ComposerAttachment {
 }
 ```
 
-这一拆分把会话 provide 通道的输入 hook 与 actions 用作实时输入区状态的唯一订阅路径，同时避免把不可序列化的浏览器对象写进持久 JSON。只有纯文本草稿镜像使用 `localStorage`；附件标识符、浏览器 `File` 对象和对象 URL 都限定在实时会话输入外壳的 scope 内。未发送图片因此无法跨重载或会话 scope 释放保留。原生客户端可以在操作系统临时目录中暂存输入，但必须像对待浏览器对象 URL 一样对待该路径：不再需要时删除，并在消息被接受前把字节复制进持久存储。
+这一拆分把会话 provide 通道的输入 hook 与 actions 用作实时输入区状态的唯一订阅路径，同时避免把不可序列化的浏览器对象写进持久 JSON。只有纯文本草稿镜像使用 `localStorage`；附件标识符、浏览器 `File` 对象和对象 URL 都限定在实时会话输入外壳的 scope 内。未发送图片因此无法跨重载或会话 scope 释放保留。切换 Workspace 时，只有目标外壳接受完整图片批次，图文混合草稿才会移动；拒绝时，文本和图片都留在来源外壳。原生客户端可以在操作系统临时目录中暂存输入，但必须像对待浏览器对象 URL 一样对待该路径：不再需要时删除，并在消息被接受前把字节复制进持久存储。
 
-本地附件后端依次解析显式 `dshHome`、`$DSH_HOME` 和 `~/.dsh`。它把内容寻址对象存储在 `$DSH_HOME/attachments/v1/objects/<prefix>/<sha256>` 下，并为目录和文件设置仅所有者可访问的权限。服务先写入并同步临时文件，再以原子方式发布，并对发布目录执行目录同步使其持久（POSIX；Windows 依赖文件系统元数据日志），之后才返回引用。内容摘要编码在不透明的 `sha256:<digest>` 标识符中。写入准入与读取都会完整解码受支持的光栅图片，之后才接受其格式和尺寸；每次读取还会校验摘要、字节长度和已记录的元数据。
+本地附件后端依次解析显式 `dshHome`、`$DSH_HOME` 和 `~/.dsh`。它把内容寻址对象存储在 `$DSH_HOME/attachments/v1/objects/<prefix>/<sha256>` 下，并为目录和文件设置仅所有者可访问的权限。每个进程首次为某个 home 保存对象时，都会创建该 home，并逐级同步每个祖先目录项直至文件系统根目录；不能把存在视为持久性，因为另一个进程可能仍处于 `mkdir` 与父目录 `fsync` 之间。随后，服务写入并同步临时文件，再以原子方式发布，并对发布路径执行目录同步使其持久（POSIX；Windows 依赖文件系统元数据日志），之后才返回引用。内容摘要编码在不透明的 `sha256:<digest>` 标识符中。写入准入与读取都会完整解码受支持的光栅图片，之后才接受其格式和尺寸；每次读取还会校验摘要、字节长度和已记录的元数据。
 
 第一版不对存储执行自动删除。已发送的用户图片和模型生成图片会一直保留，以供历史记录、恢复和 fork 使用。按引用感知的垃圾回收需要单独设计，因为仅按时间清理可能删除仍被持久会话引用的数据。部署的字节和像素限制是写入时的准入策略；读取时会校验摘要和已记录的元数据，但不重新应用当前准入限制，因此收紧策略不会导致旧历史记录失效。
 
@@ -122,7 +122,7 @@ Base64 只跨越一次 JSON-RPC，并在持久化后丢弃。宿主会校验规
 
 模型目录项增加可选且可合并扩展的输入模态声明。缺少声明表示未知；声明存在但不含 `image`，则明确表示不支持图片。
 
-宿主是权威的前置检查边界。它会解析会话最新路由到的提供方和模型，并在缺失时依次回退到 agent 选项和宿主默认值；如果该模型明确排除图片输入，宿主会在写入任何附件或事件前拒绝提示词，客户端则恢复草稿。包含图片的提示词准入与模型选择共用一个逐 agent 的串行边界，而且已经出队的提示词在其持久消息事件发布前仍保持待发布状态（[顺序决策](../bug-fix/2026-07-29-atomic-web-image-admission.md)）；steering 载体则从入队起就参与门槛，直到其 `steering/message` 事件发布为止，堵住了从不进入排队镜像的 outbox 窗口。当图片正等待发布或仍存在于会话当前的派生历史中时，模型选择会拒绝纯文本目标；压缩（compaction）可以移除旧图片，使之后选择纯文本目标变得有效，而未发布任何事件即转入空闲的准入会释放该门槛。`session.updateQueue` 的编辑只接受文本内容，因此队列编辑无法绕过该准入边界注入图片。能力未知时继续进入适配器强制检查，使未收录的模型标识符仍然可用。浏览器会在分配预览 URL 前拒绝声明不支持的图片媒体类型，但不会为部署限制或模型能力保留快照：握手快照无法表达 `session.selectModel` 之后会话的当前目标，部署策略也可能独立变化。宿主会根据当前的单张字节数、图片数量、总字节数、媒体类型、尺寸、像素数和路由模型策略校验整个批次，再写入任何附件或事件；其拒绝通过 composer 错误条呈现。
+宿主是权威的前置检查边界。它会解析会话最新路由到的提供方和模型，并在缺失时依次回退到 agent 选项和宿主默认值；如果该模型明确排除图片输入，宿主会在写入任何附件或事件前拒绝提示词，客户端则恢复草稿。包含图片的提示词准入与模型选择共用一个逐 agent 的串行边界，而且已经出队的提示词在其持久消息事件发布前仍保持待发布状态（[顺序决策](../bug-fix/2026-07-29-atomic-web-image-admission.md)）；steering 载体则从入队起就参与门槛，直到其 `steering/message` 事件发布为止，堵住了从不进入排队镜像的 outbox 窗口。当图片正等待发布或仍存在于会话当前的派生历史中时，模型选择会拒绝纯文本目标。压缩（compaction）可以移除旧图片，使之后选择纯文本目标变得有效；未发布任何事件即转入空闲时，已认领的 queued 载体会被释放，而保留在 outbox 中的 steering 在发布或丢弃前始终受门槛约束。`session.updateQueue` 的编辑只接受文本内容，因此队列编辑无法绕过该准入边界注入图片。能力未知时继续进入适配器强制检查，使未收录的模型标识符仍然可用。浏览器会在分配预览 URL 前拒绝声明不支持的图片媒体类型，但不会为部署限制或模型能力保留快照：握手快照无法表达 `session.selectModel` 之后会话的当前目标，部署策略也可能独立变化。宿主会根据当前的单张字节数、图片数量、总字节数、媒体类型、尺寸、像素数和路由模型策略校验整个批次，再写入任何附件或事件；其拒绝通过 composer 错误条呈现。
 
 Pi-AI 适配器是首条视觉输入路径：它在请求时解析 `ctx.attachments`，递归转换每个持久图片引用，包括嵌套在工具结果中的引用，并且仅为声明支持图片输入的模型生成提供方原生图片内容。交付的组合会同时注册 Pi-AI OpenAI、Anthropic 路由和仅支持文本的默认 DeepSeek 路由；选择当前提供方／模型仍由宿主组合或配置承担，而不是图片输入 CLI（命令行界面）的功能。在请求时解析服务，可避免 Cordis 加载顺序将可选附件服务的可用性固化。手写 DeepSeek 适配器遇到请求中任何位置的图片时都会抛出类型化的 `UNSUPPORTED_CONTENT` 错误，包括嵌套工具结果中的图片。任何适配器都不得将图片展平或跳过。
 
@@ -140,7 +140,7 @@ Pi-AI 适配器是首条视觉输入路径：它在请求时解析 `ctx.attachme
 
 ### 限制与信任边界
 
-第一版仅接受 PNG、JPEG、WebP 和 GIF。不接受 SVG 和远程 URL。默认限制为每张图片 5 MiB、每条消息 10 张图片和 20 MiB 图片总字节数，以及每张图片 4,000 万个固有像素。这些随部署变化的限制属于经过校验的后端配置，并由宿主在持久化前强制执行。客户端连接载体会独立限制 API 请求体的缓冲大小，并根据宿主附件服务的图片总量限制，加上 base64 和请求封装的膨胀量推导上限；未声明长度的请求体在越过上限的瞬间即被拒绝，而不是先读完再拒。
+第一版仅接受 PNG、JPEG、WebP 和 GIF。不接受 SVG 和远程 URL。默认限制为每张图片 5 MiB、每条消息 10 张图片和 20 MiB 图片总字节数，以及每张图片 4,000 万个固有像素。这些随部署变化的限制属于经过校验的后端配置，并由宿主在持久化前强制执行。客户端连接载体为每个 API 请求设置独立且可配置的 `maxRequestBodyBytes` 上限（默认 32 MiB）；如果该上限无法容纳附件服务的图片总量限制经 base64 和请求封装膨胀后的大小，加载就会失败。因此，降低图片策略绝不会静默降低有效文本或其他 RPC 的载体上限。未声明长度的请求体在越过上限的瞬间即被拒绝，而不是先读完再拒。
 
 格式错误的 base64、不支持或不匹配的媒体、截断的图片数据、超出字节限制、超出图片数量、超出像素限制、对象缺失和完整性不匹配都会返回稳定的结构化错误。原始文件名只保留用于显示的末段，控制字符会被移除，并且任何本地路径都不会写入日志或返回浏览器。