Dataflow: Persistent aggregates and explicit operator capability coverage #184

Problem

Default adoption needs correct aggregate retractions and an honest fallback matrix for remaining operators.

Evidence

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

• src/protocol/subscription/reevaluate.rs:76: The current standing-query adapter recomputes results.
• src/storage_engine/mod.rs:2350: Existing incremental-engine activation/shadow infrastructure is the starting point.

Acceptance criteria

• Maintain count/sum/min/max with existing typed numeric and set/multiplicity behavior.
• Test zero/multiple supports, float sums, min/max replacement and empty groups against the oracle.
• Publish the builtin/vector/temporal/query-local fallback matrix; split independently large operator families into follow-up issues before broadening scope.
• Compare every visible supported revision through Testing: revision-aware differential correctness oracle #167; pass Performance: baseline and mandatory pre-PR regression pipeline #163 for query/write/delta latency, throughput and memory before default adoption.

Delivery

Plan item: D05. R4 - Persistent incremental dataflow.

Dependencies / related work: #183.

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