build(vendor): rescope the vendored Cordis packages into @deepseek-ai

Machine-produced by `pnpm run rescope-vendor --apply` plus the regeneration it
prints: `pnpm install` for the lockfile, `pnpm run gen-third-party-notices`,
`verify-translation-pairing --write` for the touched bilingual pairs,
`gen-doc-graphs`, and one typert snapshot whose ids embed character offsets.
`pnpm run rescope-vendor --check` verifies the result.

Renames nine vendored packages (cordis, cosmokit, schemastery and the six
@cordisjs plugins) and every reference that resolves them: manifest names and
dependency keys, module specifiers including declare-module merges, cordis.yml
plugin names, tsconfig paths, every Markdown fence, and `docs/` prose.
Directory names, upstream versions, and dependency ranges are unchanged, so
vendor/README.md still reads as an upstream snapshot; its manifest table gains
an upstream-name column so THIRD_PARTY_NOTICES keeps MIT attribution pointed
at each fork's origin.

The tutorial tier follows the rename end to end: its yaml fences named plugins
the Loader can no longer resolve, its `ts ignore-check` fences disagreed with
the compiled fences beside them, and its prose quoted both. The contracts that
told readers to keep upstream names — the root convention and the vendoring
cookbook's tree comment and manifest invariant — now say to rescope instead.

Two rules read `@deepseek-ai/` as "another workspace plugin": the client bundle
purity gate now names the vendored libraries a browser bundle inlines, and the
files where a bare `cordis` is an agent-preset id keep that product data.

docs/cookbook/adding-a-vendored-package.zh.md

@@ -8,7 +8,7 @@
 
 ```
 vendor/<dir>/
-  package.json     # from upstream; set "private": true, keep name/exports/type
+  package.json     # from upstream; set "private": true, rescope the name, keep exports/type
   tsconfig.json    # extends ../../tsconfig.base.json (see configuration below)
   src/             # the upstream src/ verbatim
   README.md LICENSE # if upstream ships them
@@ -29,7 +29,7 @@ vendor/<dir>/
 }
 ```
 
-`package.json` 的不变式：`"private": true`（vendored 包永不发布）；保留上游的 `name`/`version`/`exports`/`type`；声明元数据指向 `lib/types`；发布 `.d.ts` 与 `.d.ts.map` 声明输出；在 `peerDependencies` 中列出其 Cordis 依赖（与上游 manifest（元数据清单）一致）。传递性上游依赖本身也必须被 vendor 或已存在于仓库中——vendor 一个包往往意味着 vendor 其整条依赖树（如 `@cordisjs/plugin-http` 会拉入 `@cordisjs/fetch-file`）。
+`package.json` 的不变式：`"private": true`（vendored 包永不发布）；改写 `name` 的 scope（[映射](../rescope.md)），保留上游的 `version`/`exports`/`type`；声明元数据指向 `lib/types`；发布 `.d.ts` 与 `.d.ts.map` 声明输出；在 `peerDependencies` 中列出其 Cordis 依赖（与上游 manifest（元数据清单）一致）。传递性上游依赖本身也必须被 vendor 或已存在于仓库中——vendor 一个包往往意味着 vendor 其整条依赖树（如 `@cordisjs/plugin-http` 会拉入 `@cordisjs/fetch-file`）。
 
 vendored TypeScript 源码中的本地相对导入/导出在复制后使用显式 `.ts` 后缀。这是仓库本地构建与上游的差异：`rewriteRelativeImportExtensions` 输出 `.js` 运行时导入，而声明文件保留显式 `.ts` 后缀，使 NodeNext/Node16 的 TypeScript 消费方能够解析。