After the recent change to to hatch for package management the main package "radidacode" is no longer installed by pip if running from the git source (pip -m pip install .).
As a solution, I propose to add "radiacode" to the target directories in pyproject.toml:
[tool.hatch.build.targets.sdist]
include = ["radiacode", "radiacode-examples/*"]
[tool.hatch.build.targets.wheel]
include = ["radiacode", "radiacode-examples/*"]
This worked for me.