Added scripts/run_molecule_parallel.py to run a runner's assigned (scenario, platform) pairs in parallel. If any subprocess fails, the remaining ones are terminated with SIGTERM/SIGKILL and the runner exits immediately. This gives fast feedback without continuing to run tests that are guaranteed to fail for the same reason. CI workflow now calls this script per matrix runner. Added fail-fast and max-parallel for best-effort cancellation across runners. Generated with [Devin](https://devin.ai) Co-Authored-By: Devin <158243242+devin-ai-integration[bot]@users.noreply.github.com>