chore: warning-free, vulnerability-free install; jest 30 without ts-jest

npm install went from 22 audit vulnerabilities (2 critical), 5 engine
warnings and 13 deprecation warnings to 0/0/1 (string-similarity, only
fixable in @dcl/eslint-config). overrides pin patched transitives
(protobufjs, semver, minimatch, zod, ajv, test-exclude, brace-expansion,
js-yaml); jest 30 compiles tests through babel-jest instead of ts-jest;
eslint 9 flat config keeps the project-local rules; node builtins replace
uuid, glob, colorette, portfinder, fp-future, open, prompts, undici and
text-encoding; snapshots regenerated (protobufjs 7.6.3 shifts bundle
sizes).

Author: Esteban Ordano

.eslintignore

@@ -49,10 +49,10 @@ The repo is orchestrated via **`make`** (the Makefile is the source of truth —
 The full Jest suite is slow. For faster iteration, scope to a path pattern:
 
 ```bash
-node_modules/.bin/jest --colors --forceExit --testPathPattern='test/sdk-commands'
-node_modules/.bin/jest --colors --forceExit --testPathPattern='test/ecs'
-node_modules/.bin/jest --colors --forceExit --testPathPattern='test/react-ecs'
-node_modules/.bin/jest --colors --forceExit --testPathPattern='test/snapshots'
+node_modules/.bin/jest --colors --forceExit --testPathPatterns='test/sdk-commands'
+node_modules/.bin/jest --colors --forceExit --testPathPatterns='test/ecs'
+node_modules/.bin/jest --colors --forceExit --testPathPatterns='test/react-ecs'
+node_modules/.bin/jest --colors --forceExit --testPathPatterns='test/snapshots'
 ```
 
 ### Per-package typecheck

.eslintrc.json

@@ -0,0 +1,61 @@
+import { FlatCompat } from '@eslint/eslintrc'
+import path from 'path'
+import { fileURLToPath } from 'url'
+
+// @dcl/eslint-config still publishes an eslintrc-style config; wrap it for eslint 9.
+const compat = new FlatCompat({ baseDirectory: path.dirname(fileURLToPath(import.meta.url)) })
+
+export default [
+  ...compat.config({
+    extends: '@dcl/eslint-config/sdk',
+    parserOptions: {
+      project: [
+        'packages/@dcl/ecs/tsconfig.json',
+        'packages/@dcl/sdk-commands/tsconfig.json',
+        'packages/@dcl/sdk/tsconfig.json',
+        'packages/@dcl/playground-assets/tsconfig.json',
+        'packages/@dcl/react-ecs/tsconfig.json',
+        'scripts/tsconfig.json',
+        'test/tsconfig.json',
+        'test/ecs/snippets/tsconfig.json'
+      ]
+    }
+  }),
+  {
+    rules: {
+      'no-param-reassign': 'warn',
+      'no-console': 'error',
+      '@typescript-eslint/no-unused-vars': [
+        'warn',
+        {
+          ignoreRestSiblings: true,
+          argsIgnorePattern: '^_',
+          varsIgnorePattern: '^_|ReactEcs',
+          caughtErrorsIgnorePattern: '^_'
+        }
+      ]
+    }
+  },
+  {
+    files: ['packages/@dcl/ecs/**/*.ts', 'packages/@dcl/sdk/**/*.ts', 'scripts/**/*.ts', 'test/**/*.ts'],
+    rules: { 'no-console': 'off' }
+  },
+  {
+    ignores: [
+      '**/*.gen.ts',
+      '**/dist/**',
+      '**/node_modules/**',
+      '**/*.d.ts',
+      '**/*.js',
+      'packages/@dcl/ecs/dist/**',
+      'packages/@dcl/ecs/src/components/generated',
+      'packages/@dcl/js-runtime',
+      'packages/@dcl/playground-assets/dist',
+      'packages/@dcl/sdk/dist/**',
+      'packages/@dcl/sdk/internal/**',
+      'packages/@dcl/sdk/testing/**',
+      'test/sdk/simple-scene',
+      'tmp'
+    ]
+  }
+]

AGENTS.md

@@ -3,9 +3,14 @@ module.exports = {
   moduleFileExtensions: ['ts', 'js', 'tsx', 'jsx'],
   transform: {
     '^.+\\.(js|jsx|ts|tsx)$': [
-      'ts-jest',
+      'babel-jest',
       {
-        tsconfig: 'test/tsconfig.json'
+        presets: [['@babel/preset-typescript', { isTSX: true, allExtensions: true, onlyRemoveTypeImports: true }]],
+        plugins: [
+          '@babel/plugin-transform-modules-commonjs',
+          '@babel/plugin-transform-dynamic-import',
+          ['@babel/plugin-transform-react-jsx', { pragma: 'ReactEcs.createElement' }]
+        ]
       }
     ]
   },