perf(server): use normal worker parallelism on Windows

packages/server/vitest.config.ts

@@ -19,9 +19,6 @@ export default defineConfig({
     setupFiles: [path.resolve(__dirname, "./src/test-utils/vitest-setup.ts")],
     pool: "forks",
     fileParallelism: false,
-    // Even two concurrent Git-heavy suites can exhaust Windows test deadlines.
-    // Run files serially so their subprocesses do not compete across suites.
-    maxWorkers: process.platform === "win32" ? 1 : undefined,
     exclude: ["**/node_modules/**", "**/dist/**", "**/.claude/**", "**/.dev/**"],
   },
 });