Builds with --enable-coverage and runs the suite under both transports
(make coverage, then make coverage-tcp). gcovr's line/branch/decision totals
are printed to the step log and also written to the GitHub step summary, so the
coverage numbers are visible directly in the CI output; the HTML reports are
uploaded as an artifact. make coverage exits with the suite's status, so a test
regression fails the job.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
