feat(ci): Add Codecov integration and native test result summaries

[hristoterezov]

Summary

This PR enhances the CI workflow with automated reporting for better visibility into test results and code coverage:

✅ Codecov integration - Automated coverage reporting with PR comments
✅ Native test summaries - Test results displayed on workflow runs

What This Adds

1. Codecov Integration

Automatic PR Comments:
Every pull request will get a comment from Codecov showing:

• Overall coverage percentage
• Coverage change compared to base branch (±X%)
• File-by-file breakdown of coverage changes
• Which lines are covered/uncovered

Codecov Dashboard:

• Coverage trends over time
• File/folder coverage breakdown
• Line-by-line visualization
• Coverage badges for README

Configuration:

• Uses codecov/codecov-action@v4 (matches other Jitsi repos like jitsi-videobridge)
• Authenticates with ${{ secrets.CODECOV_TOKEN }} from organization secrets
• Set to fail_ci_if_error: false to not block CI if Codecov has issues
• Verbose logging enabled for initial rollout debugging

2. Native Test Result Summaries

GitHub Job Summary:
Displays on the workflow run page showing:

• ✅/❌ Pass/fail status with visual indicators
• 📊 Formatted table with:
  • Total tests run
  • Number of failed tests
  • Number of passed tests

Implementation:

• Uses GitHub's native $GITHUB_STEP_SUMMARY feature
• Parses Web Test Runner console output
• No third-party actions required
• Runs with if: always() to show results even on failure

Example Output

Test Summary (on workflow run page):

### Test Results 📊

✅ All tests passed!

| Metric | Count |
|--------|-------|
| Total Tests | 42 |
| Failed | 0 |
| Passed | 42 |

Backwards Compatibility

• ✅ Existing artifact upload is preserved for manual inspection
• ✅ Test failure still causes CI to fail (exit code preserved)
• ✅ Coverage thresholds still enforced by Web Test Runner

Test Plan

• CI runs successfully on this PR
• Test summary appears on workflow run page
• Codecov uploads coverage (check for CODECOV_TOKEN availability)
• Codecov PR comment is posted
• Artifact still available for download

Related

• Matches the Codecov setup used in other Jitsi repositories (jitsi-videobridge)
• Addresses the need for visible test results without downloading artifacts

[codecov]

Welcome to Codecov 🎉

Once you merge this PR into your default branch, you're all set! Codecov will compare coverage reports and display results in all future pull requests.

Thanks for integrating Codecov - We've got you covered ☂️

[saghul]

CXan we put the long-ish scripts on files in the .github directory and call them instead?

[hristoterezov]

CXan we put the long-ish scripts on files in the .github directory and call them instead?

@saghul Done!