ci(jest): improve typings and up max concurrency for improved perf

Author: Xunnamius

jest.config.js

@@ -1,12 +1,16 @@
 'use strict';
 
+/**
+ * @type {import('jest').Config}
+ */
 module.exports = {
   restoreMocks: true,
   resetMocks: true,
   testEnvironment: 'node',
   testRunner: 'jest-circus/runner',
   // ? 24h if debugging so MMS and other tools don't choke, otherwise 1m
   testTimeout: 1000 * 60 * (process.env.VSCODE_INSPECTOR_OPTIONS ? 60 * 24 : 1),
+  maxConcurrency: require('node:os').cpus().length - 1,
   verbose: false,
   testPathIgnorePatterns: ['/node_modules/', '/dist/'],
   setupFilesAfterEnv: ['./test/setup.ts'],