chore: import upstream snapshot with attribution

showcase/shell-docs/vitest.config.ts

@@ -0,0 +1,21 @@
+import { defineConfig } from "vitest/config";
+import path from "node:path";
+
+export default defineConfig({
+  test: {
+    environment: "node",
+    include: ["src/**/*.test.{ts,tsx}"],
+    exclude: ["node_modules/**", ".next/**"],
+  },
+  resolve: {
+    alias: [
+      // Match `@/anything` so transitive imports through registry.ts /
+      // docs-render.tsx use the in-package src/ rather than tripping
+      // vite's package resolver.
+      {
+        find: /^@\/(.*)$/,
+        replacement: path.resolve(__dirname, "./src") + "/$1",
+      },
+    ],
+  },
+});