The registry proves you own a PyPI package by finding an mcp-name token in the published description, which for this project is README.md. Without it, publishing io.github.feder-cr/aihawk is refused with "Registry validation failed for package".
The token has to be on the index, not just in the tree, so it needs a release to reach anything: hence the bump to 0.43.0.
Checked on the built wheel rather than assumed, the token is in aihawk-0.43.0.dist-info/METADATA, which is the description PyPI serves and the registry reads.