Vendor Cordis framework packages as source

cordis 4.0.0-rc.6, plugin-loader, -include, -group, -timer, -hmr,
-logger-console, cosmokit 1.8.1, schemastery 3.18.0 — copied from the
cordis-workspace checkout, flattened under vendor/, original npm names,
private: true. vendor/README.md is the manifest: upstream repos +
commit SHAs, local-modification log, sync procedure.

Local modification: hmr's locale YAML imports and .i18n() call removed
(avoids a runtime YAML import hook we don't vendor).

vendor/schemastery/package.json

@@ -0,0 +1,19 @@
+{
+  "name": "schemastery",
+  "description": "Type driven schema validator",
+  "version": "3.18.0",
+  "private": true,
+  "main": "lib/index.cjs",
+  "module": "lib/index.mjs",
+  "types": "lib/index.d.ts",
+  "files": [
+    "lib",
+    "src"
+  ],
+  "author": "Shigma <shigma10826@gmail.com>",
+  "license": "MIT",
+  "dependencies": {
+    "@standard-schema/spec": "^1.1.0",
+    "cosmokit": "^1.8.1"
+  }
+}