Add Python 3.14 support

[maxrake]

Description

Add Python 3.14 support to the code base.

Additional Details

• This issue should be completed to coincide with the scheduled release of Python 3.14
  • 07 OCT 2025 from PEP 745 – Python 3.14 Release Schedule and the Python Developer's Guide
• Update the Docker base image version
• This task can be started earlier by using a release candidate version
• Update the CONTRIBUTING documentation
  • Update pyenv locally and maybe provide a notice to others to do the same
• Update the testing environments
  • in tox, GitHub workflows, etc.
• It might make sense to do Drop Python 3.10 support #604 at the same time
  • Or at least for the same release of phylum-ci
• Confirm that poetry-core supports this version of Python and includes it in the list of available Python versions
  • If needed, update pyproject.toml to ensure the minimum version of poety-core for support

Acceptance Criteria

• Python 3.14 support is added
• Tests run and pass with Python 3.14, both locally and in CI
• Documentation is updated