Set up Vitest workspace tooling

Replace Jest-specific package scripts, resolver config, and lint integration with a Vitest workspace setup. Refresh the lockfile and package metadata so the repo resolves source imports through Vitest/Vite instead of the old Jest ESM workaround.

Author: niemyjski

eslint.config.mjs

@@ -1,13 +1,11 @@
 import eslint from "@eslint/js";
 import { defineConfig } from "eslint/config";
 import eslintConfigPrettier from "eslint-config-prettier";
-import jest from "eslint-plugin-jest";
+import vitest from "@vitest/eslint-plugin";
 import tseslint from "typescript-eslint";
 
 export default defineConfig(
-  {
-    ignores: ["**/dist/", "**/node_modules/", ".agents/", "example/", "jest-resolver.cjs"]
-  },
+  { ignores: ["**/dist/", "**/node_modules/", ".agents/", "example/"] },
   eslint.configs.recommended,
   {
     extends: tseslint.configs.recommendedTypeChecked,
@@ -36,12 +34,12 @@ export default defineConfig(
   eslintConfigPrettier,
   {
     files: ["**/test/**/*.ts"],
-    extends: [jest.configs["flat/recommended"]],
+    plugins: vitest.configs.recommended.plugins,
     rules: {
-      "jest/valid-title": "off",
-      "jest/valid-describe-callback": "off",
-      "jest/no-export": "off",
-      "jest/no-done-callback": "warn"
+      ...vitest.configs.recommended.rules,
+      "vitest/valid-title": "off",
+      "vitest/valid-describe-callback": "off",
+      "vitest/no-done-callback": "warn"
     }
   }
 );

example/react/package.json

@@ -9,8 +9,7 @@
   },
   "eslintConfig": {
     "extends": [
-      "react-app",
-      "react-app/jest"
+      "react-app"
     ]
   },
   "browserslist": {
@@ -26,7 +25,6 @@
     ]
   },
   "devDependencies": {
-    "@testing-library/jest-dom": "^6.9.1",
     "@testing-library/react": "^16.3.2",
     "@testing-library/user-event": "^14.6.1",
     "@vitejs/plugin-react": "^6.0.1",