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tell a fresh writer from one replaying a snapshot a predecessor superseded.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.

packages/llm/llm-deepseek/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/llm/llm-deepseek/README.md
-README.md: 11bed74b4952624208f23f093b787eb978cfef69
-README.zh.md: 5fa75ad3434fe9610ba8005d436af51fd7a134f9
+README.md: 46666459d524dab952d555cc7f196d45e53d606a
+README.zh.md: 4210974c274513dc47383a23711baa6b14515307

packages/llm/llm-deepseek/README.md

@@ -109,7 +109,7 @@ Loop-retained response blocks append to the next request and preserve its earlie
 ## Known Limitations and Deferred Work
 
 - **A settings `models` list replaces the composition list wholesale** — settings-layer merging is per-field, and arrays are one field; per-entry catalog merging would need a keyed shape.
-- **`Config.apiKey` is schema-tagged `role('secret')` but not yet masked anywhere** — the settings `describe()` envelope returns values verbatim; the wire/UI layer that must redact secret-role fields ships with the settings RPC surface.
+- **`Config.apiKey` is redacted on the wire but still a stored literal** — `describe({ redactSecrets: true })` strips it and reports the slot, so a configuration UI never receives the value; the key is nonetheless stored in the settings document rather than the credential store, so prefer `apiKeyEnv`.
 - **`tool_choice` is not mapped** — not part of the core vocabulary (MVP cut, shared with the pi-ai twin).
 - **Requests use raw `fetch`, not `@cordisjs/plugin-http`** — no shared proxy/interception configuration; adoption is deferred until a second adapter wants it (`TODO(http)`).
 - **Serialization flattens user and tool-result content to text blocks** — plugin-added block types are skipped, and empty tool output crosses the wire as the literal `(no output)`.

packages/llm/llm-deepseek/README.zh.md

@@ -109,7 +109,7 @@ loop 保留的响应块会追加到下一个请求，并保留其较早可复用
 ## 已知限制与暂缓事项
 
 - **settings 的 `models` 列表会整体替换组合列表**：settings 层按字段合并，而数组是单个字段；按条目合并 catalog 需要带键的形状。
-- **`Config.apiKey` 已在 schema 中标注 `role('secret')`，但尚未在任何地方脱敏**：settings 的 `describe()` 信封原样返回值；负责对 secret 角色字段脱敏的 wire／UI 层将随 settings RPC 面一起交付。
+- **`Config.apiKey` 在协议上已脱敏，但仍是一个已存的字面值**：`describe({ redactSecrets: true })` 会把它剥离并报告该槽位，配置 UI 因此永远收不到该值；但这个密钥仍存放在 settings 文档而非凭据存储中，所以请优先使用 `apiKeyEnv`。
 - **未映射 `tool_choice`**：它不属于核心词汇（MVP 取舍，与 pi-ai twin 共享）。
 - **请求使用原始 `fetch`，而非 `@cordisjs/plugin-http`**：没有共享 proxy／拦截配置；采用暂缓到第二个适配器需要该功能时（`TODO(http)`）。
 - **序列化会将 user 与工具结果内容展平为文本块**：会跳过插件添加的块类型，空工具输出会以字面 `(no output)` 通过协议发送。