Release playkit v0.3 with Zod asserts and auth helpers

Add assertSchema/ApiClient schema option, storageState helpers, and
playkitFailureArtifacts preset for consumer e2e suites.

package.json

@@ -1,6 +1,6 @@
 {
   "name": "@levkin/playkit",
-  "version": "0.2.1",
+  "version": "0.3.0",
   "description": "Shared Playwright + API test kit — browser helpers, API client, logging, performance, Grafana/Prometheus metrics",
   "license": "MIT",
   "type": "module",
@@ -47,6 +47,9 @@
     "prepublishOnly": "npm run build",
     "example:api": "tsx examples/api/health.example.ts"
   },
+  "dependencies": {
+    "zod": "^3.24.0"
+  },
   "peerDependencies": {
     "@playwright/test": ">=1.40.0"
   },