feat: add model-free receipt v1 verifier fixtures

[nighshift-labs]

Summary

• add a dependency-free cryoflux.receipt.v1 canonical JSON and content-addressed evidence manifest verifier
• distinguish VALID, INVALID, and UNVERIFIABLE outcomes without synthesizing missing evidence
• preserve signed/negative observations and explicitly warn when energy evidence is unavailable
• add adversarial synthetic fixtures for metric/artifact tampering, canonicalization changes, missing evidence, lineage shape, reordering, and NaN rejection

Validation

• python3 -m unittest discover -s tests -p "test_receipt_v1.py" -v (8/8)
• python3 -m py_compile cryo-orchestrator/receipt_v1.py tests/test_receipt_v1.py
• git diff --check

This first slice does not claim honest hardware, honest execution, or scientific claim sufficiency from hashes alone. Historical v0.1 receipts are untouched.