resolvePendingInteraction deletes the pending entry before dispatch, but
resolvePetName then re-ran LoadAndDelete to recover the carried PetType.
That second lookup always missed, so the if !ok branch returned nil: the
save never ran and no pet was ever persisted (adoption was 100% broken).
Pass the already-loaded interaction in, matching every other handler.
Add a regression test driving the real dispatcher path.
