feat(challenge36): add solution on trackby

apps/performance/ngfor-optimize/jest.config.ts

@@ -0,0 +1,22 @@
+/* eslint-disable */
+export default {
+  displayName: 'performance-ngfor-optimize',
+  preset: '../../../jest.preset.js',
+  setupFilesAfterEnv: ['<rootDir>/src/test-setup.ts'],
+  coverageDirectory: '../../../coverage/apps/performance/ngfor-optimize',
+  transform: {
+    '^.+\\.(ts|mjs|js|html)$': [
+      'jest-preset-angular',
+      {
+        tsconfig: '<rootDir>/tsconfig.spec.json',
+        stringifyContentPathRegex: '\\.(html|svg)$',
+      },
+    ],
+  },
+  transformIgnorePatterns: ['node_modules/(?!.*\\.mjs$)'],
+  snapshotSerializers: [
+    'jest-preset-angular/build/serializers/no-ng-attributes',
+    'jest-preset-angular/build/serializers/ng-snapshot',
+    'jest-preset-angular/build/serializers/html-comment',
+  ],
+};