Implement WebAuthn passkey authentication

Add complete WebAuthn support for passkey registration and authentication:
- Install @simplewebauthn/server for WebAuthn utilities
- Create passkey-helpers.ts with base64url/Uint8Array conversion utilities
- Create webauthn.ts with registration/authentication option generation and verification
- Create context.ts with API context types
- Implement all WebAuthn router handlers (createRegistrationOptions, verifyRegistration, createAuthenticationOptions, verifyAuthentication)
- Implement passkey management handlers (listPasskeys, createPasskey, renamePasskey, deletePasskey)
- Add WebAuthn configuration constants and environment variables

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

apps/api-server/package.json

@@ -13,7 +13,11 @@
   "dependencies": {
     "@orpc/server": "^1.13.2",
     "@reviq/api-contract": "workspace:*",
-    "@reviq/db": "workspace:*"
+    "@reviq/db": "workspace:*",
+    "@reviq/db-schema": "workspace:*",
+    "@simplewebauthn/server": "^13.2.2",
+    "@simplewebauthn/types": "^12.0.0",
+    "kysely": "^0.28.2"
   },
   "devDependencies": {
     "@macalinao/eslint-config": "catalog:",