Give tests headroom on slow CI runners

Each test builds a fresh database through every migration; the hosted
Windows runner needs well over the 5s default for that.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

vitest.config.ts

@@ -4,5 +4,6 @@ export default defineConfig({
   test: {
     environment: "node",
     include: ["tests/{unit,contract,integration,eval}/**/*.test.ts"],
+    testTimeout: 30_000,
   },
 });