feat(settings): detect stale writers with a revision, and announce raw changes

The remaining P1 from the #939 review, plus the P2 it shares a mechanism with.

Nothing carried a version, so two tabs editing one namespace silently
overwrote each other — reproduced as tab B's `reasoning` lost to tab A's
older draft. The seam's per-namespace write queue orders writes; it cannot
tell a fresh writer from one replaying a snapshot a predecessor superseded.

Each namespace now carries a monotonic `revision` over its RAW section. A
write may send `expectedRevision`, checked at the FRONT of the queue (not at
call time, which would race the very predecessor it guards against); a
mismatch rejects with `SettingsConflictError` → `settings-conflict` on the
wire, carrying both revisions. The editor captures the revision it opened at
and, on conflict, asks the user to reopen rather than replaying its snapshot.

The same counter fixes the missing broadcast. `settings/updated` is gated on
the resolved value — correct for consumers, wrong for configuration surfaces:
storing an override equal to the composition base leaves the resolved value
alone while changing what the document says (the field is now overridden, not
inherited) and moving every open editor's revision. `settings/document-updated
(ns, revision)` fires on any raw-section change, in-process or external, and
`host/settings-changed` now rides it.

That event also closes the stale model picker: editing a provider's `models`
changes no route, so `llm/adapters-updated` never fired and an open picker
kept serving the old catalog. A change to an exposed provider namespace now
emits `host/models-changed` too — that namespace holds the catalog.

Docs: both sides of the five touched README pairs, a type-equiv block for
`SettingsPathOp`, and an Agent Note recording what the plane exposes and who
may overwrite what. The deferred wire-redaction gaps (secrets behind
union/intersection/transform, `.default(...)` in the served envelope, schema
text in rejection messages, `new Function` rehydration, pi-ai's `headers`) are
recorded as TODO(settings-wire-redaction) and in Known Limitations rather than
half-fixed.

.agents/notes/implemented/architecture/2026-07-30-config-plane-boundaries.i18n.yaml

@@ -0,0 +1,6 @@
+# Bilingual-pair consistency record (docs/i18n/README.md): the git blob hash of each
+# 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/architecture/2026-07-30-config-plane-boundaries.md
+2026-07-30-config-plane-boundaries.md: 8a29dcc934126d6e3dfa9c0a6a308ef006017a5a
+2026-07-30-config-plane-boundaries.zh.md: c858b7dd5b6fcd61936c33f1f09d7d2e89a3cfc7

.agents/notes/implemented/architecture/2026-07-30-config-plane-boundaries.md

@@ -0,0 +1,41 @@
+# Agent Note: what the configuration plane exposes, and who may overwrite what
+
+Status: implemented
+
+English | [中文](2026-07-30-config-plane-boundaries.zh.md)
+
+> Scope: the review round over the [web configuration plane](2026-07-30-web-config-plane.md) — which namespaces reach the wire, which callers reach them, and how an editor holding a partial, possibly stale view writes without destroying what it cannot see.
+
+## Problem
+
+The plane worked and was reachable by more callers, and with more authority, than its design claimed.
+
+`trustedHosts` gated only writes, so a declared LAN client could call `settings.describe` — every exposed namespace's configuration — and `credentials.describe`, which reports whether an arbitrary environment-variable name is configured and where it resolves from. That fence is a DNS-rebinding defense and says so; treating it as an authorization boundary for reads was a category error. Separately, the proxy served every registered namespace: the settings seam is deliberately general, so the first plugin to call `settings.register()` for its own configuration would silently become remotely readable and writable, without passing anywhere near a review of the web surface.
+
+The editor was worse than reachable — it was destructive. It reads the redacted descriptor, which by construction omits `role('secret')` fields. Clearing one field rebuilt the whole user section from that redacted copy and sent `settings.replace`, so a stored literal `apiKey` the wire had never returned was deleted as a side effect. Reproduced directly: `{baseURL, reasoning}` in, `apiKey` gone. Row removal took the same path. And nothing carried a version, so two tabs editing one namespace silently overwrote each other; the seam's per-namespace write queue orders writes but cannot tell a fresh writer from one replaying a stale snapshot.
+
+Three smaller defects sat beside them. `llm/adapters-updated` documented contained observer failures but only caught synchronous ones, so an async listener's rejection escaped as an unhandled rejection. llm-deepseek's retry-policy swap disposed its registration before re-registering, publishing an empty route set between the two — an observer saw the provider disappear and come back, despite a comment claiming no such window. And a transport rejection during the page's credential enrichment escaped `load()`, stranding the page in `loading` with no error shown.
+
+## Decision
+
+**Reading configuration is as privileged as writing it.** `settings.describe` and `credentials.describe` join the loopback-only set, so the whole configuration plane stays same-origin until real authentication exists. The model catalog (`llm.providers`, `llm.models`) deliberately does not: it carries provider ids, display names, and model lists — no endpoints, no key state — and a LAN client's model picker needs it. The boundary is asserted over a real HTTP server rather than a hand-assembled request, because the `Host` header a browser actually sends is what decides it.
+
+**The plane serves exactly the namespaces a registered model provider addresses.** `ctx.llm.listConfigurableProviders()` is the allow-list, so the product boundary is enforced rather than inferred from today's plugin set, and a future namespace becomes web-configurable only by joining that directory. An unregistered namespace and an unexposed one answer identically (`settings-not-exposed`), so probing cannot enumerate the registry.
+
+**A caller with a partial view names the field it means.** `Settings.mutate(ns, ops)` applies `set`/`unset` path ops to the section as it stands at the front of the write queue. The client builds ops by diffing its opening snapshot against its draft, so it mentions only fields it can see: a secret absent from both sides produces no op and survives by construction, not by care. `replace` remains the deliberate wholesale reset.
+
+**Staleness is detected, not ordered away.** Each namespace carries a monotonic `revision` over its RAW section; writes may carry `expectedRevision`, and a mismatch rejects with `SettingsConflictError` → `settings-conflict` on the wire, both revisions attached. The editor captures the revision it opened at and, on conflict, tells the user to reopen rather than replaying its snapshot.
+
+**The raw layer gets its own event.** `settings/updated` stays gated on the resolved value — that is what a consumer means by change. `settings/document-updated (ns, revision)` fires on any raw-section change, because a configuration surface must learn that a field went from inherited to overridden (same resolved value, different meaning) and that its held revision is stale. The host frame `host/settings-changed` now rides this event, and a change to an exposed provider namespace also emits `host/models-changed`: that namespace holds the provider's catalog, which no route change announces.
+
+## Alternatives considered
+
+- **A deployment-declared namespace allowlist on the proxy config** — more general, but it moves the product boundary to whoever writes cordis.yml, and an empty default would break the shipped page until every deployment opted in. The provider directory already states exactly which namespaces are model configuration.
+- **Opt-in metadata at `settings.register()`** — the most honest semantics (the namespace's owner declares its own exposure), and the largest change: the seam's public interface, both LLM plugins, and their docs. Recorded as the shape to adopt if a non-LLM namespace ever needs the plane.
+- **Distinguishing "unregistered" from "registered but unexposed"** — better diagnostics, and a namespace-enumeration oracle. The uniform answer is deliberate.
+- **Detecting conflicts by diffing instead of a revision** — comparing the submitted base against storage would work for whole-section writes, but the editor holds a REDACTED section: it cannot produce a comparable base, which is the same reason it cannot safely `replace`. A counter needs neither.
+- **Fixing the redaction gaps in this round** — `redactSecrets` walks only `object`/`dict`/`array`, so a secret behind a union, intersection, or transform is returned verbatim with an empty `secrets` list; `schema.toJSON()` carries a secret field's `.default(...)`; write-rejection messages return schema text that may quote the input; the client rehydrates the envelope through schemastery's `new Function`; and pi-ai's plain-string `headers` dict can legitimately hold `Authorization`. All confirmed, all deliberately left for a fail-closed `describeForWire()` that refuses a schema it cannot prove safe. They are recorded as `TODO(settings-wire-redaction)` and in the owning READMEs' Known Limitations rather than half-fixed here.
+
+## Consequences
+
+A LAN client on a `trustedHosts` deployment can no longer render the settings page at all; loopback is the configuration surface. A plugin that registers a settings namespace is not web-configurable until it also registers a configurable provider — deliberate, and the reason `settings-not-exposed` names the boundary in its message. `SettingsDescriptor` gained a required `revision`, so any programmatic constructor of a descriptor-shaped value must supply it, and `settings/document-updated` is a new event any provider-side listener may now observe. Clients that ignore `expectedRevision` keep last-write-wins semantics unchanged. Deferred: the fail-closed wire describe (with the `headers` and envelope-sanitization work it carries), and a non-executable browser schema protocol.

.agents/notes/implemented/architecture/2026-07-30-config-plane-boundaries.zh.md

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+# Agent Note：配置面暴露什么，以及谁有权覆盖什么
+
+Status: implemented
+
+[English](2026-07-30-config-plane-boundaries.md) | 中文
+
+> 范围：针对 [Web 配置面](2026-07-30-web-config-plane.md)的评审轮——哪些 namespace 能抵达协议、哪些调用方能抵达它们，以及一个只持有局部、且可能过期视图的编辑器该如何写入，才不会毁掉它看不见的东西。
+
+## 问题
+
+这个面能用，但能触达它的调用方、以及它们所拥有的权限，都比设计声称的更多。
+
+`trustedHosts` 只拦住了写入，因此一个已声明的 LAN 客户端可以调用 `settings.describe`——拿到每个已暴露 namespace 的配置——以及 `credentials.describe`，后者会报告任意一个环境变量名是否已配置、又从何处解析。那道 fence 是 DNS 重绑定防御，它自己也是这么写的；把它当作读取的授权边界，是一次范畴错误。另一件事是：代理服务于每一个已注册的 namespace。settings seam 是刻意做成通用的，因此第一个为自身配置调用 `settings.register()` 的插件，就会悄无声息地变成可远程读写，而完全不必经过任何针对 Web 表层的评审。
+
+编辑器比"可触达"更糟——它是破坏性的。它读到的是脱敏后的 descriptor，后者按构造省略了 `role('secret')` 字段。清空其中一个字段，会用这份脱敏副本重建整个用户分节并发出 `settings.replace`，于是一个协议从未回传过的已存字面 `apiKey` 被顺带删除。这一点被直接复现：输入 `{baseURL, reasoning}`，输出时 `apiKey` 消失。删除整行走的是同一条路径。而且没有任何东西携带版本，因此两个标签页编辑同一个 namespace 会静默互相覆盖；seam 的逐 namespace 写队列只排定写入次序，分辨不出一个新写方与一个重放过期快照的写方。
+
+另有三个较小的缺陷与之并列。`llm/adapters-updated` 的文档写着观察者失败会被收容，却只捕获同步失败，于是异步 listener 的 rejection 作为 unhandled rejection 逃逸。llm-deepseek 的重试策略换路由先释放注册、再重新注册，在两者之间发布了一个空路由集——观察者会看到该提供方消失又回来，尽管注释宣称不存在这样的空窗。还有，页面做凭据增强时的传输层 rejection 会逃出 `load()`，把页面卡在 `loading` 且不显示任何错误。
+
+## 决策
+
+**读配置与写配置同样特权。**`settings.describe` 与 `credentials.describe` 加入仅限回环的集合，因此在真正的认证层出现之前，整个配置面都保持同源。模型目录（`llm.providers`、`llm.models`）刻意不在其中：它携带的是提供方 id、显示名与模型列表——没有端点、没有密钥状态——而 LAN 客户端的模型选择器正需要它。这条边界由一台真实 HTTP 服务器来断言，而不是手工拼装的请求，因为真正决定它的，是浏览器实际发出的那个 `Host` 头。
+
+**这个面恰好服务于已注册模型提供方所指向的那些 namespace。**`ctx.llm.listConfigurableProviders()` 就是允许列表，于是产品边界是被执行的，而不是从今天的插件集合里推断出来的；将来的 namespace 只有加入该目录才会变得可在 Web 上配置。未注册的 namespace 与未暴露的 namespace 得到完全相同的答复（`settings-not-exposed`），因此探测无法枚举注册表。
+
+**持有局部视图的调用方，点名它真正要改的字段。**`Settings.mutate(ns, ops)` 会把 `set`/`unset` 路径 op 施加在写入排到队首那一刻的分节上。客户端通过对比自己打开时的快照与草稿来构造 op，因此它只提及自己看得见的字段：两侧都没有的机密不会产生任何 op，它的留存是构造使然，而非小心使然。`replace` 仍是那个刻意的整体重置。
+
+**过期是被检测出来的，而不是靠排序绕过去的。**每个 namespace 都带有一个针对其**原始**分节的单调 `revision`；写入可携带 `expectedRevision`，不匹配即以 `SettingsConflictError` 拒绝——在协议上是 `settings-conflict`，并附上两个 revision。编辑器记住自己打开时的 revision，冲突时请用户重新打开，而不是把自己的快照重放上去。
+
+**原始层拥有自己的事件。**`settings/updated` 仍以解析值为门槛——那才是消费方所说的"变化"。`settings/document-updated (ns, revision)` 则在任何原始分节变化时触发，因为配置界面必须知道某个字段从继承变成了覆盖（解析值相同，含义不同），也必须知道自己持有的 revision 已经过期。host 帧 `host/settings-changed` 现在搭乘这个事件；而已暴露提供方 namespace 的变更还会额外发出 `host/models-changed`：该 namespace 正持有这个提供方的目录，而没有任何路由变更会宣告它。
+
+## 曾考虑的替代方案
+
+- **在代理配置上做部署声明式的 namespace 白名单**——更通用，但它把产品边界交给了写 cordis.yml 的人，而空的默认值会让已交付的页面在每个部署显式开启之前直接失效。提供方目录本就精确地说明了哪些 namespace 属于模型配置。
+- **在 `settings.register()` 处 opt-in metadata**——语义最正（由 namespace 的属主自行声明其暴露与否），改动也最大：seam 的公共接口、两个 LLM 插件，以及它们的文档。记录为：一旦某个非 LLM 的 namespace 确实需要这个面，就采用这个形状。
+- **区分"未注册"与"已注册但未暴露"**——诊断更好，同时也是一台 namespace 枚举预言机。统一答复是刻意为之。
+- **用 diff 而非 revision 来检测冲突**——对整分节写入而言，拿提交时的基线与存储比对是可行的，但编辑器持有的是**脱敏后**的分节：它给不出可比对的基线，这与它不能安全地 `replace` 是同一个原因。计数器两者都不需要。
+- **本轮就修掉脱敏的缺口**——`redactSecrets` 只遍历 `object`/`dict`/`array`，因此藏在 union、intersection 或 transform 之后的机密会被原样返回，且 `secrets` 列表为空；`schema.toJSON()` 会带上 secret 字段的 `.default(...)`；写入拒绝的消息返回的是可能引用了输入的 schema 文本；客户端通过 schemastery 的 `new Function` 重建信封；而 pi-ai 那个纯字符串的 `headers` 字典完全可以合法地放下 `Authorization`。全部经确认属实，也全部刻意留给一个 fail-closed 的 `describeForWire()`——它会拒绝自己无法证明安全的 schema。它们被记录为 `TODO(settings-wire-redaction)` 以及各属主 README 的 Known Limitations，而不是在这里做一半。
+
+## 影响
+
+`trustedHosts` 部署下的 LAN 客户端已经完全无法渲染设置页；配置表层就是回环。注册了 settings namespace 的插件，在它同时注册可配置提供方之前不会变得可在 Web 上配置——这是刻意的，也正是 `settings-not-exposed` 要在消息里点明这条边界的原因。`SettingsDescriptor` 新增了必填的 `revision`，因此以编程方式构造 descriptor 形状值的地方都必须提供它；`settings/document-updated` 是一个新事件，provider 侧的任何 listener 现在都可以观察它。忽略 `expectedRevision` 的客户端，其后写胜出的语义完全不变。延后事项：fail-closed 的协议 describe（连同它所承载的 `headers` 与信封净化工作），以及一套客户端无法执行的浏览器 schema 协议。