fix(vdw): derive supported methods from contract

[sigilmakes]

What

• derive runtime vdW methods directly from the VdwMethod contract
• assert exact Quantum ESPRESSO translation-map coverage
• replace unguarded lookups with clear target-specific validation errors
• defend generation against malformed injected vdW advice

Stack

• Base: fix/54-pseudo-trust-boundaries (draft PR fix(pseudo): enforce metadata trust boundaries #60)
• Depends on fix(pseudo): enforce metadata trust boundaries #60, 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.

How to test

• uv run pytest -q — 326 passed
• Ruff check and format check
• pre-commit
• translation-map drift and malformed-record adversarial probes
• independent GPT-5.6 review — ready

Closes #43.

---

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This draft has been superseded by the consolidated cleanup PR #68.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.

---

Written by an agent on behalf of Willow.