Initial vitest setup

app/package.json

@@ -9,7 +9,9 @@
     "preview": "vite preview",
     "type-check": "tsc --noEmit",
     "lint": "eslint . --ext .ts,.tsx",
-    "lint:fix": "eslint . --ext .ts,.tsx --fix"
+    "lint:fix": "eslint . --ext .ts,.tsx --fix",
+    "test": "vitest run",
+    "test:watch": "vitest"
   },
   "repository": {
     "type": "git",
@@ -54,6 +56,8 @@
   },
   "devDependencies": {
     "@eslint/compat": "^1.2.9",
+    "@testing-library/jest-dom": "^6.6.3",
+    "@testing-library/react": "^16.3.0",
     "@types/babel__core": "^7.20.5",
     "@types/node": "^22.14.0",
     "@types/react": "^18.3.20",
@@ -65,13 +69,15 @@
     "eslint": "^9.27.0",
     "eslint-plugin-react": "^7.37.5",
     "eslint-plugin-react-hooks": "^5.2.0",
+    "jsdom": "^26.1.0",
     "postcss": "^8.4.47",
     "postcss-preset-mantine": "^1.17.0",
     "postcss-simple-vars": "^7.0.1",
     "sass": "^1.80.4",
     "typescript": "^5.8.2",
     "vite": "^6.2.4",
-    "vite-plugin-compression2": "^1.3.0"
+    "vite-plugin-compression2": "^1.3.0",
+    "vitest": "^3.1.4"
   },
   "browserslist": {
     "production": [