The Acks page needs two merge hooks (one per ack flavor) and both
shapes use numeric database ids rather than the string ids that
Claim/Remittance/Activity use. The generic constraint widens to
`T extends { id: string | number }` and the dedup Set normalizes
to String(id) so a base item with id=2 and a tail item with id=2
collide correctly.
Adds two switch cases that mirror the claims/remittances keyed-by-id
pattern: iterate the order array, look up the matching value in the
dict, drop undefined holes defensively.
Two tests assert the new slices order by their order arrays and dedup
against base items.
Nora
Tyler