Two projected settlement identities carry no witness

[flyingrobots]

Observed

PR #27 adds four identities to the observation settlement report. Only one of them is bound to anything:

Field	Witnessed by	Bound to
externalEvidenceDigest	stale-basis two-route case	bytes actually observed
basisDigest	shape only	the value the request declared
attemptId	shape only	nothing
schemaAdmissionEvidenceDigest	shape only	nothing

assert_settlement_evidence requires all four to match ^[0-9a-f]{64}$ and nothing more. A producer emitting one arbitrary constant for attemptId and schemaAdmissionEvidenceDigest across every settlement passes the entire suite.

Why it matters

This is the I0 level of evidence — the field exists and is well-formed — presented alongside a field that reaches I2. Uniform-looking assertions over non-uniform evidence strength is exactly what made #26 hard to see in the first place.

schemaAdmissionEvidenceDigest is the more interesting of the two. It is derived by schema_admission_evidence(profile.settlement_schema_digest, &result) over the settlement result bytes, so it should vary with the result and be constant for identical results under the same schema. That is a checkable claim and nothing checks it.

attemptId has no obvious claim beyond uniqueness per attempt. It may be correct to state that it carries no semantic claim rather than to witness it.

Not done in #27 deliberately

#27's claim is precise and adversarially verified. Growing it to cover fields with no stated claim would have widened the PR without strengthening it. Filing instead.

Acceptance

• schemaAdmissionEvidenceDigest is pinned to vary with the settlement result and to be stable across identical results under one schema; or
• the documentation states which projected identities carry no witness and why, so that shape-only assertions are not mistaken for bindings.

[coderabbitai]

🔗 Related PRs

#17 - Prove durable Hello Echo execution [merged]
#21 - Prove typed Hello Echo result recovery [merged]
#22 - Prove bounded workspace observation [merged]
#24 - Prove basis-bound validated patch application [merged]
#27 - Bind observation settlements to their basis evidence [open]

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