Document preferred PR process for backports

[Copilot]

Overview

This PR adds documentation to guide developers when submitting backport PRs to release/YYMM branches, addressing issue #XXX.

Changes

Added a new "Backport PR Best Practices" section to the Release Management documentation (Guide/src/dev_guide/contrib/release.md) that clarifies:

1. Clean cherry-picks are strongly preferred - Explicitly states that clean cherry-picks minimize reviewer effort and reduce the risk of introducing regressions.

2. Non-clean cherry-picks must be clearly indicated - Instructs developers to note in the PR description when a backport required conflict resolution or additional modifications, signaling to reviewers that extra care is needed during the review process.

Rationale

The new documentation helps streamline the backport process by:

• Setting clear expectations for contributors about the preferred approach
• Helping reviewers quickly identify PRs that may require more thorough review
• Reducing the likelihood of regression issues in release branches

The section is positioned immediately after the "Seeking Approval for Backport" section, making it a natural part of the backport workflow documentation.

Original prompt

---

This section details on the original issue you should resolve

<issue_title>Document preferred PR process for Backports</issue_title>
<issue_description>Add documentation to guide developers when submitting backport PRs to release/X branches.

• Clean cherry-picks preferred, as it saves the reviewer time
• If not a clean cherry-pick, indicate that so the reviewer can invest more care reviewing</issue_description>

Comments on the Issue (you are @copilot in this section)

Fixes #2175

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[Copilot]

Pull Request Overview

This PR documents best practices for submitting backport PRs to release branches, addressing the need for clearer guidance on the backport process. The documentation emphasizes clean cherry-picks and transparent communication about non-clean backports.

• Adds a new "Backport PR Best Practices" section to the release management documentation
• Establishes that clean cherry-picks are preferred to minimize reviewer effort and reduce regression risk
• Requires developers to flag non-clean cherry-picks in PR descriptions for enhanced reviewer awareness

[mattkur]

Looks good here. It would be better if there were some systems in place to safeguard against this, but ... certainly nothing wrong with these docs. Thanks Ben!

[benhillis]

Looks good here. It would be better if there were some systems in place to safeguard against this, but ... certainly nothing wrong with these docs. Thanks Ben!

I've been pretty impressed at Copilot writing this type of stuff.