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.

vendor/schemastery/package.json

@@ -1,5 +1,5 @@
 {
-  "name": "schemastery",
+  "name": "@deepseek-ai/schemastery",
   "description": "Type driven schema validator",
   "version": "3.18.0",
   "private": true,
@@ -27,6 +27,6 @@
   "license": "MIT",
   "dependencies": {
     "@standard-schema/spec": "^1.1.0",
-    "cosmokit": "^1.8.1"
+    "@deepseek-ai/cosmokit": "^1.8.1"
   }
 }

vendor/schemastery/src/index.ts

@@ -1,4 +1,4 @@
-import { Binary, clone, deepEqual, filterKeys, isNullable, isPlainObject, pick, valueMap, type Dict } from 'cosmokit'
+import { Binary, clone, deepEqual, filterKeys, isNullable, isPlainObject, pick, valueMap, type Dict } from '@deepseek-ai/cosmokit'
 import type { StandardSchemaV1 } from '@standard-schema/spec'
 
 const kSchema = Symbol.for('schemastery')