Harden Microplex H5 compatibility gates

[MaxGhenis]

Summary

• strengthen the mp artifact compatibility gate to validate all PE structural entity arrays, ID uniqueness, person-to-entity joins, weight validity, requested-period coverage, non-finite numeric values, and leaked source-diagnostic variables such as ssi_reported
• accept repeated loader-smoke payloads with median_runtime_ratio and nested candidate/baseline timing fields
• preserve product names from manifests, so record-count products like mp-120k are not rewritten as mp-300k
• index persisted mp artifact gate reports in the living dashboard run board

Validation

• /Users/maxghenis/.local/bin/uv run --python 3.13 --extra dev ruff check src/microplex_us/pipelines/mp300k_artifact_gates.py src/microplex_us/pipelines/dashboard.py tests/pipelines/test_mp300k_artifact_gates.py tests/pipelines/test_dashboard.py
• /Users/maxghenis/.local/bin/uv run --python 3.13 --extra dev ruff format --check src/microplex_us/pipelines/mp300k_artifact_gates.py src/microplex_us/pipelines/dashboard.py tests/pipelines/test_mp300k_artifact_gates.py tests/pipelines/test_dashboard.py
• /Users/maxghenis/.local/bin/uv run --python 3.13 --extra dev pytest -q tests/pipelines/test_mp300k_artifact_gates.py tests/pipelines/test_dashboard.py

Real artifact checks

• Wrote /Users/maxghenis/CosilicoAI/microplex-us/artifacts/mp120k_latest_us_data_refit_20260528/mp300k_artifact_gates.json: passed all six required gates, compatibility pass, loss 0.0935698176 vs eCPS 0.1663667311, runtime ratio 1.1928, size ratio 1.3608.
• Wrote /Users/maxghenis/CosilicoAI/microplex-us/artifacts/small_asec_acs40k_bea_lsr_20260523/pe_native_l0_source_weight_start_strong_penalty1000_latest_us_data_e5000_probe/mp300k_artifact_gates.json: compatibility pass and loss 0.0713187395 vs eCPS 0.1698235134, but failed release gates on size 2.0002 and runtime 2.2562.
• Refreshed /Users/maxghenis/CosilicoAI/microplex-us/artifacts/microplex_dashboard_current.json; the gate reports now appear under run_board.mp300k_artifact_gate_reports.