Incompatible dependency in GUI extras: gradio-client==1.8.0 on Python 3.8

### Description When installing the GUI extra dependencies on Python 3.8: ```bash pip install -e .[gui] ``` the installation fails with: ```bash ERROR: Could not find a version that satisfies the requirement gradio-client==1.8.0 ``` ### Root Cause Although `gradio-client==1.8.0` exists on PyPI, it does not provide distributions for `Python 3.8` (no cp38 wheels). As a result, pip cannot resolve this dependency on Python 3.8 environments. At the same time, the project does not specify a minimum Python version in setup.py, and the minimal installation works correctly on `Python 3.8`. This makes the current GUI extra dependency specification incompatible with `Python 3.8`. ### Environment - Python version: 3.8 - OS: Linux - Installation method: pip install -e .[gui] ### Suggested Fix (optional) One possible solution is to make the gradio-client dependency conditional based on Python version, or relax the strict version pinning for Python 3.8.