Add repository support to deb distributions

[mehuljariwala]

Summary

Adds the repository option to pulp.squeezer.deb_distribution, allowing an APT distribution to track and serve the latest version of a named DEB repository.

Fixes #250.

Implementation

• Documents the new option and adds a repository-backed distribution example.
• Resolves repository names through PulpAptRepositoryContext and sends the resulting Pulp href to the distribution API.
• Supports an empty value for clearing an existing repository association.
• Makes repository and publication mutually exclusive, matching Pulp's API and the existing rpm_distribution module behavior.
• Adds focused tests for repository resolution, clearing, and the module's mutual-exclusion contract.

Validation

• pytest -v tests/test_deb_distribution.py — 2 tests passed.
• make test_deb_distribution — replay and check-mode tests passed.
• make lint — passed, including playbook syntax, Black, isort, Galaxy importer, and ansible-lint.
• make sanity — full Ansible sanity suite passed on Python 3.13.
• git diff --check — passed.

The Galaxy importer emitted the repository's existing warning that the collection has no changelog file; import completed successfully.

Compatibility and risk

The option is additive. Existing publication-backed distributions are unchanged. The implementation mirrors the established RPM distribution path and uses the pulp-glue-deb repository context already used elsewhere in this collection.

AI assistance

OpenAI Codex assisted with repository analysis, implementation, and test orchestration. The changes were reviewed against the existing RPM implementation and current Pulp DEB documentation, and were validated with the commands above.

[mdellweg]

Read the documentation first.

(Good first time issues are meant for actual human contributors btw.)

[mehuljariwala]

You are right that I missed the organization-level AI policy requirement: the AI-assistance disclosure needed to be in the commit message, not only in the PR description. This contribution was AI-assisted, and this automated workflow cannot itself provide the human review and personal responsibility your policy requires. I will close the PR and step back from the issue rather than imply compliance. Apologies for not finding the organization-wide policy before submitting.

[mehuljariwala]

Closing to respect the Pulp AI contribution policy and the maintainer’s request.