docs: record the forwarded-event surface and its face boundaries

Each owner package's README states which of its cordis events are forwarded and
that the declaration now lives in the client-safe ./types export. api/remotes
documents the allowlist as the single control point and the deliberate
both-faces listing of src/types.ts; development.md keeps the split-tsconfig rule
current.

packages/credentials/credentials/README.md

@@ -25,7 +25,7 @@ await ctx.credentials.set(ref, 'sk-…')                   // rejects while a re
 await ctx.credentials.unset(ref)                         // no-op when absent; same shadowing rule
 ```
 
-`credentials/updated (ref)` fires after a committed change to a provider-managed source — a `set`, an `unset`, or an external edit observed in storage. Ambient process-environment changes are not observable and never emit. Consumers do not need the event (they re-resolve per operation); it exists for configuration UIs refreshing a "configured" badge.
+`credentials/updated (ref)` fires after a committed change to a provider-managed source — a `set`, an `unset`, or an external edit observed in storage. Ambient process-environment changes are not observable and never emit. Consumers do not need the event (they re-resolve per operation); it exists for configuration UIs refreshing a "configured" badge. Its declaration lives in the client-safe `./types` subpath export together with the `CredentialRef` type it names (the package root re-exports the type), so a consumer outside the Host compilation face reads the very signature the Host emits instead of restating it.
 
 The shadowing rule on `set`/`unset` is deliberate fail-loud: when a read-only source (the live process environment, in the local provider) currently supplies the reference, a write would appear to succeed while resolution keeps returning the shadowing value — the seam rejects instead, and `describe().writable` lets a UI render the reference read-only up front.
 

packages/credentials/credentials/README.zh.md

@@ -25,7 +25,7 @@ await ctx.credentials.set(ref, 'sk-…')                   // rejects while a re
 await ctx.credentials.unset(ref)                         // no-op when absent; same shadowing rule
 ```
 
-`credentials/updated (ref)` 在提供方管理的来源发生已提交变更后触发——`set`、`unset` 或在存储中观察到的外部编辑。进程环境变量的变化不可观测，永不触发。消费方不需要该事件（它们按操作重新解析）；它服务于配置界面刷新「已配置」徽标。
+`credentials/updated (ref)` 在提供方管理的来源发生已提交变更后触发——`set`、`unset` 或在存储中观察到的外部编辑。进程环境变量的变化不可观测，永不触发。消费方不需要该事件（它们按操作重新解析）；它服务于配置界面刷新「已配置」徽标。它的声明住在 client-safe 的 `./types` 子路径出口，与其点名的 `CredentialRef` 类型同处一处（包根继续 re-export 该类型），于是 Host 编译面之外的消费方读到的正是 Host 发射的那一份签名，而不必再写一遍。
 
 `set`/`unset` 的遮蔽规则是刻意设计为明确报错：当只读来源（本地提供方中即当前进程环境）正在提供该引用时，写入会表面成功而解析仍返回遮蔽值——seam 选择直接拒绝，并通过 `describe().writable` 让界面提前把该引用渲染为只读。