test: revert to threads

vmThreads mode swallows console.logs during test debugging

vitest.config.ts

@@ -24,7 +24,6 @@ export default defineConfig({
   },
   plugins: [codspeedPlugin()],
   test: {
-    pool: 'vmThreads',
     globals: true,
     setupFiles: 'scripts/setup-vitest.ts',
     environmentMatchGlobs: [