docs: Update copilot instructions

[nev21]

No description provided.

[Copilot]

Pull request overview

Updates the repository’s Copilot instructions by replacing the old “Release Process” snippet with a more detailed “Creating a Release PR” checklist to guide versioning, changelog updates, and validation before publishing.

Changes:

• Replaces the brief release-process steps with a structured “Creating a Release PR” section.
• Adds guidance for semver selection, updating versions across packages, and changelog formatting.
• Adds build/test verification steps (rush update, clean build, full test run, artifact checks).

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 91.43%. Comparing base (5b0ca1a) to head (dd86d78).
⚠️ Report is 1 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main     #268   +/-   ##
=======================================
  Coverage   91.43%   91.43%           
=======================================
  Files          78       78           
  Lines        3445     3445           
  Branches      887      887           
=======================================
  Hits         3150     3150           
  Misses        295      295           

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.
• 📦 JS Bundle Analysis: Save yourself from yourself by tracking and limiting bundle sizes in JS merges.

[nev21]

LGTM

[nevware21-bot]

Approved by nevware21-bot