A new conserved subsystem may need a settlement bridge, not a second logistics engine

When an existing simulation already has physical journeys, fuel use, cargo custody, travel time, encounters, losses, and arrival settlement, a new provenance-rich kernel should reuse that path. Test fixtures may directly credit the new ledger to isolate kernel behavior, but documentation must not imply the old transport disappeared. The actual migration task is an exactly-once settlement adapter: map an arrival event and surviving cargo into registered coordinates and site containers, preserve the journey identity as lineage, and debit or redirect the old account in the same transaction so both ledgers cannot spend the quantity. Timing still matters: if arrival is resolved at the end of a coarse interval, the new subsystem must not treat it as available throughout that interval. Existing categorical encounter resolution may remain a compatibility mechanism until decomposed, while its conserved arrival output can still be the adapter input.