chore: add PR description template check workflow

[louislam]

Summary

AI slop issue is getting worst, I have no choice.

Please follow this checklist to avoid unnecessary back and forth (click to expand)

• ⚠️ If there are Breaking change (a fix or feature that alters existing functionality in a way that could cause issues) I have called them out
• 🧠 I have disclosed any use of LLMs/AI in this contribution and reviewed all generated content.
  I understand that I am responsible for and able to explain every line of code I submit.
• 🔍 Any UI changes adhere to visual style of this project.
• 🛠️ I have self-reviewed and self-tested my code to ensure it works as expected.
• 📝 I have commented my code, especially in hard-to-understand areas (e.g., using JSDoc for methods).
• 🤖 I added or updated automated tests where appropriate.
• 📄 Documentation updates are included (if applicable).
• 🧰 Dependency updates are listed and explained.
• ⚠️ CI passes and is green.

[Copilot]

Pull request overview

This PR adds a GitHub Actions workflow to automatically enforce the use of the PR template by checking for a specific phrase ("avoid unnecessary back and forth") and closing PRs that don't include it. This is part of the repository's effort to combat AI-generated "slop" PRs that don't follow proper contribution guidelines.

Changes:

• Adds a new workflow file .github/workflows/pr-description-check.yml that validates PR descriptions on PR open events
• Implements automatic PR closure for PRs missing the required template phrase
• Excludes certain bot accounts (UptimeKumaBot, Copilot, copilot-swe-agent) from the check