Major refactor: HTTP-only cookies, passkey management, and UI improvements

- Refactor session management from WebSocket tokens to HTTP-only cookies
- Move user/credential endpoints from WebSocket to HTTP REST API
- Add comprehensive passkey management (add/delete with safety checks)
- Implement AAGUID-based authenticator info with icons and names
- Add human-readable date formatting and clean grid layout
- Create modular architecture with session_manager, api_handlers, aaguid_manager

pyproject.toml

@@ -17,6 +17,7 @@ dependencies = [
     "base64url>=1.0.0",
     "aiosqlite>=0.19.0",
     "uuid7-standard>=1.0.0",
+    "pyjwt>=2.8.0",
 ]
 requires-python = ">=3.10"