Schema narrower than spec after #364: reproducibility and appraisal.method/re_execution rejected #366

Summary

Once #364 merges, schema/trace-claim.json (and its packaged copy) is narrower than the spec: a conformant record carrying the section 3.1.4 members is rejected.

The 11 September ruling on #247 gives this condition a severity: "A schema that is narrower than the spec rejects conformant records. That is a defect with a severity, not a documentation nit, and it should be filed as one." This is that filing.

Measured (at #364 head)

• examples/amd-sev-snp.json validates clean.
• Add reproducibility (section 3.1.4 shape): Additional properties are not allowed ('reproducibility' was unexpected).
• Add appraisal.method and appraisal.re_execution: ('method', 're_execution' were unexpected).
• A record omitting the members is unaffected.

Fix

Schema, models.py and docs/schema.md gain the members in the shape section 3.1.4 fixes:

• reproducibility {function, code_identity, optional code_resolver, input_closure[] {id, digest, resolver}, transcript_digest}
• appraisal.method (closed set, one value re-execution)
• appraisal.re_execution {outcome in reproduced | diverged | not-attempted, observed_digest (required when diverged), reason (required when not-attempted), optional verifier_code_identity}, present iff method is re-execution

Plus producer vectors carrying the claim and an appraisal that re-ran it. Sponsor-free under CONTRIBUTING (schema changes tracking a merged spec change). I take it, sequenced immediately after #364.

Blocked on #364. Refs #249.