fix(dashboard): Import vendored shadcn CSS from design-tokens

The dashboard stylesheet imported "shadcn/tailwind.css", but shadcn was never
a declared dependency — it only reached the dashboard transitively via
@vendure-io/design-tokens. Version 2.0.0-beta.8 of design-tokens dropped that
dependency, so any install resolving the ^2.0.0-beta.7 range forward lost the
package entirely and the stylesheet failed to build.

design-tokens 2.0.0-beta.9 vendors the same CSS and exposes it as
./css/shadcn, so import it from there and raise the minimum to beta.9.

Author: michaelbromley

bun.lock

@@ -96,7 +96,7 @@
         "@types/react": "^19.2.14",
         "@types/react-dom": "^19.0.4",
         "@uidotdev/usehooks": "^2.4.1",
-        "@vendure-io/design-tokens": "^2.0.0-beta.7",
+        "@vendure-io/design-tokens": "^2.0.0-beta.9",
         "@vendure-io/ui": "^2.0.0-beta.16",
         "@vitejs/plugin-react": "^5.2.0",
         "acorn": "^8.16.0",

packages/dashboard/package.json

@@ -1,7 +1,7 @@
 @import '@vendure-io/design-tokens/css/fonts';
 @import 'tailwindcss';
 @import 'tw-animate-css';
-@import "shadcn/tailwind.css";
+@import '@vendure-io/design-tokens/css/shadcn';
 
 html[dir="rtl"] * {
     direction: rtl;