Bump vitest testTimeout to 30s for slow PBKDF2 (600k iters) derivations

The crypto suite's deriveKey tests exceeded vitest's default 5s per-test
timeout in CI (passed locally only because the host is faster). Set a 30s
per-test timeout so the PBKDF2-heavy tests don't flake the pipeline.

vite.config.js

@@ -43,5 +43,8 @@ export default defineConfig(({ command }) => ({
     globals: true,
     setupFiles: ['./tests/setup.js'],
     include: ['src/**/*.test.js', 'tests/**/*.test.js'],
+    // PBKDF2 (600k iterations) derivations are slow; don't let the default 5s
+    // per-test timeout flake the suite on slower CI hosts.
+    testTimeout: 30000,
   },
 }))