Added Vitest to web/, ready for tests

web/package.json

@@ -11,7 +11,9 @@
     "lint": "eslint .",
     "format": "prettier --write .",
     "format:check": "prettier --check .",
-    "check": "npm run typecheck && npm run lint && npm run format:check",
+    "test": "vitest run",
+    "test:watch": "vitest",
+    "check": "npm run typecheck && npm run lint && npm run format:check && npm run test",
     "generate:api": "node scripts/generateApiTypes.ts",
     "sync": "node scripts/syncDist.ts"
   },
@@ -35,6 +37,7 @@
     "typescript": "^5.5.4",
     "typescript-eslint": "8.71.0",
     "vite": "^6.0.0",
-    "vite-plugin-solid": "^2.11.0"
+    "vite-plugin-solid": "^2.11.0",
+    "vitest": "4.1.11"
   }
 }