Unauthenticated log-flood DoS via directory asset paths

Denial of service in NiceGUI before 3.12.0 allows remote attackers to consume disk and log-pipeline capacity via crafted asset requests. The ESM and per-component resource routes join an untrusted sub-path to a registered base directory, accept directories because Path.exists() returns true, and pass them to Starlette FileResponse, which raises an uncaught RuntimeError logged as a full traceback. No authentication or user interaction is required; repeated requests against a publicly reachable server can exhaust log storage or saturate downstream logging, without confidentiality or integrity loss.