chore: add testing deps

Author: brettkolodny

package.json

@@ -7,7 +7,12 @@
     "dev": "vite",
     "build": "tsc -b && vite build && vite build --mode=client",
     "lint": "eslint .",
-    "preview": "vite preview"
+    "preview": "vite preview",
+    "test": "vitest",
+    "test:ui": "vitest --ui",
+    "test:run": "vitest run",
+    "test:coverage": "vitest run --coverage",
+    "test:watch": "vitest watch"
   },
   "dependencies": {
     "@fontsource-variable/inter": "^5.2.5",
@@ -60,6 +65,8 @@
     "@biomejs/biome": "2.1.1",
     "@eslint/js": "^9.25.0",
     "@hono/vite-dev-server": "^0.19.1",
+    "@testing-library/jest-dom": "^6.6.4",
+    "@testing-library/react": "^16.3.0",
     "@types/lodash": "^4.17.17",
     "@types/node": "^22.15.21",
     "@types/prismjs": "^1.26.5",
@@ -73,12 +80,14 @@
     "eslint-plugin-react-hooks": "^5.2.0",
     "eslint-plugin-react-refresh": "^0.4.19",
     "globals": "^16.0.0",
+    "happy-dom": "^18.0.1",
     "postcss": "^8.5.3",
     "tailwindcss": "3",
     "typescript": "~5.8.3",
     "typescript-eslint": "^8.30.1",
     "vercel": "^42.3.0",
     "vite": "^6.3.5",
-    "vite-plugin-vercel": "^9.0.7"
+    "vite-plugin-vercel": "^9.0.7",
+    "vitest": "^3.2.4"
   }
 }