Use vite 6 compatible vitest 3.0.0-beta.1 and fix .json import

Author: techniq

packages/svelte-ux/package.json

@@ -49,7 +49,7 @@
     "typescript": "^5.7.2",
     "unist-util-visit": "^5.0.0",
     "vite": "^6.0.3",
-    "vitest": "^2.1.8"
+    "vitest": "^3.0.0-beta.1"
   },
   "type": "module",
   "dependencies": {

packages/svelte-ux/src/routes/+layout.server.ts

@@ -2,7 +2,7 @@ import { redirect } from '@sveltejs/kit';
 
 import { env } from '$env/dynamic/private';
 
-import themes from '../../themes.json';
+import themes from '../../themes.json' with { type: 'json' };
 import { getThemeNames } from '$lib/styles/theme.js';
 
 export async function load({ url }) {