Remove unnecessary setuptools dependency pin

[adiaholic]

Summary

• Removes the exact setuptools = "80.9.0" pin from pyproject.toml
• Regenerates poetry.lock to reflect the change

Motivation

setuptools is not imported anywhere in the modelscan source code and the build system uses poetry-core, so it is not needed as a declared runtime dependency. The exact pin propagates upstream to consumers and causes dependency conflicts for end users who have other packages with different setuptools version requirements.

Example error reported by customers:

ERROR: pip's dependency resolver does not currently take into account all the packages that are installed.
guardian-client 1.7.0 requires setuptools<79.0.0,>=74.1.2, but you have setuptools 80.9.0 which is incompatible.

setuptools will still be available transitively through other packages (e.g., torch, tensorboard) that declare permissive version ranges — this change only removes the restrictive exact pin from modelscan itself.

Testing

• Verified setuptools is not imported in any source file (grep -r "import setuptools\|from setuptools\|pkg_resources" modelscan/ returns no results)
• Verified poetry lock resolves successfully after the change

[jacob-protectai]

Will note that's a pretty old version of guardian-client.

[rakeshwalisheter]

lgtm. This pin was added to resolved a compliance P0 issue but can be removed now.