fix(tests): use dynamic imports in portal.test.ts to avoid env validation

vitest.config.ts

@@ -1,5 +1,7 @@
 import { defineConfig } from 'vitest/config';
 import path from 'path';
+// eslint-disable-next-line @typescript-eslint/no-require-imports
+const { loadEnv } = require('vite');
 
 export default defineConfig({
   test: {
@@ -12,13 +14,10 @@ export default defineConfig({
       provider: 'v8',
       reporter: ['text', 'lcov', 'json-summary'],
       include: ['src/lib/**'],
-      exclude: [
-        'src/lib/db/migrations/**',
-        'src/lib/db/schema/**',
-        'src/**/*.d.ts',
-      ],
+      exclude: ['src/lib/db/migrations/**', 'src/lib/db/schema/**', 'src/**/*.d.ts'],
     },
     testTimeout: 30_000,
+    env: loadEnv('test', process.cwd(), ''),
   },
   resolve: {
     alias: { '@': path.resolve(__dirname, './src') },