The Acks page needs the same live-tail triplet as Claims/Remittances/
Activity. Both Ack and Ta1Ack have stable numeric ids from the
database row, so they get the keyed-by-id treatment (first write
wins, FIFO-capped at TAIL_CAP) — same shape as the claims and
remittances slices, not the append-only activity array.
Adds addAck, addTa1Ack, ackOrder, ta1AckOrder, and the matching
reset cases for the new 'acks' / 'ta1_acks' TailResource kinds.
evictOldest is now generic over T so the same helper covers the
two new keyed-by-id slices without duplication.
Nora
Tyler