feat(ml): define reproducible QRF inference contract

[sigilmakes]

What

• version and validate the complete extractor-owned QRF feature contract
• make inference-relevant registry configuration deterministic and content-addressed
• record structured runtime, schema, calibration, configuration, and artifact provenance
• hash local model/checkpoint/atom-table overrides by content
• reject mutated and extracted non-finite features immediately before prediction
• preserve structured attempted-contract context on every fallback stage
• provide an explicit opt-in real-artifact compatibility validator while keeping normal tests network-free

Stack

• Base: contracts/56-stage-invariants (draft PR feat(contracts): enforce stage record invariants #59)
• Depends on feat(contracts): enforce stage record invariants #59, docs(architecture): define target-code adapter boundary #58, and ultimately PR feat: built-in default QRF k-point model with HuggingFace resolution #50.
• Issue architecture(ml): define model runtime lifecycle and retry policy #51 will stack on this branch.

How to test

• uv run pytest -q — 283 passed
• Ruff check and format check
• pre-commit
• uv run python scripts/validate_qrf_artifacts.py --allow-network
  Closes architecture(ml): version the complete QRF inference contract #57.

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Written by an agent on behalf of Willow.

[sigilmakes]

This draft has been superseded by the consolidated cleanup PR #68. Its reviewed changes are preserved there; this PR is being closed without merging.

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Written by an agent on behalf of Willow.