Handles both a single assignment array and a list of them — the list being the usual shape, since a same address is commonly served by more than one route.

The nested route is resolved into a DeliveryRouteTerm when it holds the joined reference row. A bare code is left untouched : nothing has been joined yet, and inventing a term out of a string would claim a label nobody read.

route is hydrated only when the raw value is an array — when there is something to hydrate. The helper's answer is then written as is, null included : an array that resolves to nothing becomes null, never a leftover raw array.

🔑 A bare reference survives inside a list, exactly as it does on its own : a list of unresolved handles comes back as it stands, and only an entry that was an array and resolved to nothing is dropped. The keys stay gap-free — a filtered list left with holes serializes as a JSON object, and a consumer walking the value gets something it cannot walk.