Add Copilot code review instructions for pull requests

[Copilot]

Enables GitHub Copilot code review context per the Copilot instructions file spec.

Changes

• .github/copilot-instructions.md — Review context for Copilot covering R code standards, roxygen2 documentation, backward compatibility, testthat requirements, and dependency management

Enabling Copilot Code Review

GitHub Copilot code review is a native feature enabled through repository settings, not via a GitHub Actions workflow. To enable:

1. Go to Settings → Copilot → Code review
2. Enable "Copilot code review"

The copilot-instructions.md file will provide context and guidelines that Copilot uses during reviews.

• Fixes talgalili/dendextend#158

Original prompt

---

This section details on the original issue you should resolve

<issue_title>[FEATURE] add copilot review to be run automatically</issue_title> <issue_description>Some context:

https://github.blog/ai-and-ml/unlocking-the-full-power-of-copilot-code-review-master-your-instructions-files/</issue_description>

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

• Fixes talgalili/dendextend#158

---

💡 You can make Copilot smarter by setting up custom instructions, customizing its development environment and configuring Model Context Protocol (MCP) servers. Learn more Copilot coding agent tips in the docs.

[Copilot]

Fix

Current runner version: '2.329.0'...

Fixed in 86b94f0. The github/copilot-code-review-action doesn't exist as a public action - Copilot code review is a native GitHub feature enabled in repository settings, not via a workflow.

The .github/copilot-instructions.md file remains and will provide context for Copilot during reviews. To enable Copilot code review:

1. Go to Settings → Copilot → Code review
2. Enable "Copilot code review"

[codecov[bot]]

Codecov Report

:white_check_mark: All modified and coverable lines are covered by tests. :white_check_mark: Project coverage is 99.40%. Comparing base (0af62aa) to head (86b94f0).

Additional details and impacted files

@@           Coverage Diff           @@
##           master     #159   +/-   ##
=======================================
  Coverage   99.40%   99.40%           
=======================================
  Files          50       50           
  Lines        4184     4184           
=======================================
  Hits         4159     4159           
  Misses         25       25           

:umbrella: View full report in Codecov by Sentry.
:loudspeaker: Have feedback on the report? Share it here.

:rocket: New features to boost your workflow:

• :snowflake: Test Analytics: Detect flaky tests, report on failures, and find test suite problems.