ADR-0180 §1.5.4 + CLAUDE.md work-sequencing item 5 require these four
properties green on main before any core-rs/src/vault.rs change. They are
also the foundation ADR-0181 PR-5 (audio Delta-CRDT wiring) rides on.
T-1 set-equality of vault writes under shuffled ingest (+ idempotent
re-ingest at the content-addressed layer)
T-2 trace-hash invariance to vault order, + recall result-set invariance
to insertion order (the genuinely-failable half)
T-3 versor_apply non-commutativity (negative guard)
T-4 ProjectionHead.project purity across calls and threads
Findings (docs/audit/ADR-0180-t1-t4-findings.md):
- compute_trace_hash folds only vault_hits (a count), NOT vault contents, so
ADR-0180 §1.5.3's "re-sort vault state in content-addressed order" is
currently vacuous at the trace-hash layer; the live order-invariance
obligation is at recall() (result-set + count). Recommend amending §1.5.3.
- equal-score recall ties are index-sensitive; the Merge Kernel needs a
content-addressed tiebreak (mirrors ADR-0181 §2.2 merge key). Recommend
amending §2.2.
- append is genuinely semilattice-eligible; versor_apply is non-commutative.
7 passed; smoke suite green. No runtime/core mutation — tests + audit only.
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