Add comprehensive WebAuthn e2e/unit tests and virtual authenticator package

- Create @reviq/virtual-authenticator package with cryptographically valid
  WebAuthn credential generation for testing
- Add e2e tests for WebAuthn registration, authentication, passkey management
- Add unit tests for passkey-helpers and VirtualAuthenticator
- Add security tests for counter replay and tampered responses
- Configure test database environment in devenv.nix
- Add turbo.json test tasks and workspace configuration

Test results: 98 tests passing (54 virtual-authenticator, 25 e2e, 19 unit)

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

packages/testing/virtual-authenticator/src/index.ts

@@ -0,0 +1,8 @@
+export type { VirtualAuthenticatorOptions } from "./virtual-authenticator.js";
+export {
+  base64urlToUint8Array,
+  DEFAULT_AAGUID,
+  parseAaguid,
+  uint8ArrayToBase64url,
+  VirtualAuthenticator,
+} from "./virtual-authenticator.js";