Replace z.any() with z.custom<T>() for WebAuthn types

Use proper TypeScript types from @simplewebauthn/types instead of
z.any() for WebAuthn-related schemas:
- PublicKeyCredentialCreationOptionsJSON
- PublicKeyCredentialRequestOptionsJSON
- RegistrationResponseJSON
- AuthenticationResponseJSON

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

packages/api-contract/package.json

@@ -17,6 +17,7 @@
   },
   "dependencies": {
     "@orpc/contract": "^1.13.2",
+    "@simplewebauthn/types": "^12.0.0",
     "libphonenumber-js": "^1.12.33",
     "zod": "^4.3.5"
   },