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>

turbo.json

@@ -18,6 +18,17 @@
     },
     "clean": {
       "cache": false
+    },
+    "test:e2e": {
+      "dependsOn": ["^build"],
+      "inputs": ["src/**/*.ts", "src/**/*.test.ts"],
+      "env": ["TEST_DATABASE_URL"],
+      "cache": false
+    },
+    "test:unit": {
+      "dependsOn": ["^build"],
+      "inputs": ["src/**/*.ts", "src/**/*.test.ts"],
+      "cache": false
     }
   }
 }