Design decisions

Each record states a decision, why it was made, and what it costs. Records are not edited after the fact except to mark them superseded; a changed decision gets a new record. Proposals not yet decided live in docs/design.

#	Decision	Status
0001	One admission queue, one batch assembled at a time	Accepted
0002	Verify with tests, model checking and mutation testing together	Partly superseded by 0009
0003	Per-key batching with one batch in flight per key	Accepted
0004	Dispatch a key's next batch when its previous one completes	Accepted
0005	Pair per-key batching with a fenced, idempotent write	Accepted
0006	Report outcomes per input; fail a batch only when it did not happen	Accepted
0007	Bound batches and the waiting room by weight as well as count	Accepted
0008	Deferred: sharding, lock-free admission, adaptive concurrency, and more	Deferred
0009	Drop mutation testing	Accepted
0010	Send an idle key's input directly; batch only keys with concurrent work	Accepted
0011	A key's waiting inputs are sent in a pluggable order	Accepted
0012	Package "read once, apply, conditional write" as FoldWrite	Accepted
0013	Rename BulkDike to Ferry	Accepted
0014	Package "commit, then project" as ProjectedWrite, marker in the store	Accepted
0015	Project per entry: a projection may land for some entries, and Committed says why	Accepted