chore: add stale workflow to manage inactive issues/PRs

[DefinitelyADev]

Add a GitHub Actions workflow, 'stale.yml', to automatically manage stale issues and pull requests. This workflow marks issues and PRs as stale after 30 days of inactivity and closes them if no action is taken within an additional 5 days. This change helps maintain repository hygiene by reducing the number of inactive issues and PRs. Exempt labels include 'enhancement' and 'bug'.

[Copilot]

Pull Request Overview

This PR adds a GitHub Actions workflow to automatically manage inactive issues and pull requests by marking them as stale after 30 days of inactivity and closing them after an additional 5 days without activity.

• Introduces automated stale issue and PR management using the actions/stale@v10 action
• Configures 30-day inactivity threshold before marking as stale, with 5-day grace period before closure
• Exempts issues and PRs labeled with 'enhancement' or 'bug' from automatic closure

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[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 72.13%. Comparing base (a8d0f51) to head (224ed15).
⚠️ Report is 1 commits behind head on master.

Additional details and impacted files

@@           Coverage Diff           @@
##           master      #18   +/-   ##
=======================================
  Coverage   72.13%   72.13%           
=======================================
  Files           6        6           
  Lines         664      664           
  Branches       73       73           
=======================================
  Hits          479      479           
  Misses        167      167           
  Partials       18       18           

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