Support backporting specfile only patches and identify patches from Fedora

[lbarcziova]

Fixes packit/jotnar#164

Tested with https://gitlab.com/redhat/centos-stream/rpms/bzip2/commit/a297cb19307d0ec5a21f7e383e12a62597225c7f.patch

[gemini-code-assist]

Code Review

This pull request introduces a valuable optimization for backporting patches. It adds the capability to detect patches from dist-git sources (like Fedora) and apply specfile-only changes directly, bypassing the more complex cherry-pick or git-am workflows. This is achieved by adding a new DistgitDetectorTool and updating the agent's instructions. The changes are well-structured and the new logic is clearly documented in the agent's prompt. I've made one suggestion to improve code quality in the new tool.

[gemini-code-assist]

The try...except Exception block is too broad and can hide unexpected bugs. According to Python best practices (like PEP 8 E722), you should avoid except Exception:. In this case, the try block is quite safe as url is validated as a string by Pydantic and urllib.parse.urlparse is robust against malformed URLs. The try...except block is likely unnecessary. Removing it makes the code cleaner and safer against masking unrelated errors.

        parsed = urlparse(url.lower())
        hostname = parsed.hostname or ""
        path = parsed.path.lower()

        # Fedora dist-git
        if "src.fedoraproject.org" in hostname:
            return True

        # RHEL/CentOS Stream GitLab
        if "gitlab.com" in hostname:
            return "/redhat/centos-stream/rpms/" in path or "/redhat/rhel/rpms/" in path

        # Not a recognized dist-git source
        return False