Update README with virtual environment setup instructions (#243)

Added instructions for setting up a virtual environment and installing dependencies.

error: No virtual environment found; run `uv venv` to create an environment, or pass `--system` to install into a non-virtual environment

README.md

@@ -98,6 +98,7 @@ If you prefer a modern Python workflow, GenericAgent also provides a minimal `py
 ```bash
 git clone https://github.com/lsdefine/GenericAgent.git
 cd GenericAgent
+uv venv
 uv pip install -e ".[ui]"        # Core + GUI dependencies
 cp mykey_template.py mykey.py
 python launch.pyw