Add mp-300k artifact gates

[MaxGhenis]

Summary

• add a persistent mp-300k artifact-gate CLI that writes mp300k_artifact_gates.json
• gate candidate existence, PolicyEngine H5 compatibility, artifact size, runtime smoke, eCPS comparison, and frozen benchmark-manifest evidence
• add microplex-us-package-mp300k-gate-inputs so producer jobs can package artifact.tar.gz plus evidence JSONs as one Actions artifact
• update the reusable GitHub Actions workflow to consume either URL inputs or a packaged gate_inputs_artifact

Producer handoff

A candidate-producing job can now do:

- run: |
    uv run microplex-us-package-mp300k-gate-inputs       --artifact-dir "$ARTIFACT_DIR"       --ecps-comparison-json "$ECPS_COMPARISON_JSON"       --runtime-smoke-json "$RUNTIME_SMOKE_JSON"       --benchmark-manifest "$BENCHMARK_MANIFEST_JSON"       --output-dir gate-inputs
- uses: actions/upload-artifact@v4
  with:
    name: mp300k-gate-inputs
    path: gate-inputs

Then call this workflow with:

uses: ./.github/workflows/mp300k-artifact-gates.yml
with:
  gate_inputs_artifact: mp300k-gate-inputs

Local artifact run

Ran the new package command on small-asec-acs40k-bea-lsr-v1 using its real L0 candidate H5, existing PE-native broad-loss scores, and runtime smoke evidence. Then extracted the generated /tmp/mp300k_gate_inputs_small_asec_acs40k/artifact.tar.gz and ran artifact gates from the packaged archive.

The packaged handoff report is at /tmp/mp300k_gate_inputs_small_asec_acs40k/mp300k_artifact_gates.json and correctly fails the candidate on artifact size, runtime smoke, and eCPS comparison while passing artifact existence and structural compatibility.

Key local result:

• compatibility: pass, packaged candidate H5 found under the extracted archive
• artifact size: fail, 2.0002x eCPS versus 2.0x threshold
• runtime smoke: fail, 105.5x eCPS on entity-table loader smoke
• eCPS comparison: fail, candidate broad loss 10.15 versus eCPS 0.17
• benchmark manifest: unmeasured

Checks

• uv run --python 3.13 --extra dev python -m pytest tests/pipelines/test_mp300k_artifact_gates.py tests/pipelines/test_mp300k_gate_inputs.py
• uv run --python 3.13 --extra dev --with pydantic --with-editable ../microplex pytest -q tests/pipelines/test_mp300k_artifact_gates.py tests/pipelines/test_mp300k_gate_inputs.py
• uv run --python 3.13 --extra dev ruff check pyproject.toml src/microplex_us/pipelines/mp300k_artifact_gates.py src/microplex_us/pipelines/mp300k_gate_inputs.py tests/pipelines/test_mp300k_artifact_gates.py tests/pipelines/test_mp300k_gate_inputs.py
• uv run --python 3.13 --extra dev ruff format --check src/microplex_us/pipelines/mp300k_artifact_gates.py src/microplex_us/pipelines/mp300k_gate_inputs.py tests/pipelines/test_mp300k_artifact_gates.py tests/pipelines/test_mp300k_gate_inputs.py
• git diff --check
• workflow YAML parsed with Ruby YAML

Notes

uv lock --check --python 3.13 still wants to update the editable sibling ../microplex from v0.1.0 to v0.2.0. This PR keeps uv.lock scoped to the new direct h5py dependency instead of accepting unrelated local editable metadata churn.