Testing: revision-aware differential correctness oracle #167

Problem

Persistent incremental evaluation needs an independent correctness oracle before it becomes the serving path. Existing standing-query tests and shadow-write checks do not compare every visible revision against both recomputation and a finite naive reference.

Evidence

Source: 5c1f313379a5cb2995a43a66ddba0b5cc9798b7f (inspected 2026-10-03). These are source findings; the acceptance scenarios below still need implementation and execution.

• src/storage_engine/mod.rs:3779: Existing tests enable the incremental engine for shadow writes.
• src/protocol/subscription/reevaluate.rs:76: The serving standing-query adapter currently executes a query and diffs the rows.
• tests/standing_query_tests.rs:1: Live WebSocket tests provide useful fixtures to reuse.

Acceptance criteria

• Define adapters for recompute, a naive finite reference and incremental execution with a named committed revision and explicit set/multiplicity semantics.
• Run fixed seeds and minimized randomized histories covering duplicate support, recursive deletion, negation, aggregates, rule replacement and restart.
• Reuse existing .iql.out behavior fixtures; explicitly distinguish unsupported reference operators instead of treating them as successful comparisons.
• Inject a deliberately wrong adapter and demonstrate a failing, minimized history. Add persistent derived-graph adapters as D01–D08 land.
• Keep this test-only and record the Performance: baseline and mandatory pre-PR regression pipeline #163 attestation; Epic: long-lived per-KG incremental dataflows (real streaming reasoning) #143 remains open until its complete capability, performance and soak acceptance passes.

Delivery

Plan item: O01. R1 - Safety + perf/e2e gates.

Dependencies / related work: #163.

Contributes to #143; completing this slice alone does not close the broader issue.