ci: Improve changelog suggestion

[jfldde]

Description

• Extract non-LLM changes from ci: Integrate Gemini API to generate changelog suggestions in PR checks. #3016
• Restrict scope of changelog suggestion to PR with title prefix ^(feat|fix|perf)
• Prevent bot to comment if /skip-changelog is present

Linked Issues

• Fixes Restrict scope of changelog suggestions #3061
• Fixes Prevent changelog suggestion when /skip-changelog is already present #3037

[jfldde]

/skip-changelog

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 83.6%. Comparing base (0375066) to head (00ed73f).
⚠️ Report is 6 commits behind head on nightly.

Additional details and impacted files

see 3 files with indirect coverage changes

🚀 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.