Add a dedicated "Enforce coverage floor" step to tests.yml that parses
the coverage XML report and fails the build if line coverage drops below
60%. This runs after tests succeed and provides a clear, visible check
separate from pytest's own --cov-fail-under flag.
Fixes#935
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
ced4a8a7dc