Promote ship to the user-facing delivery skill. Kind is short or long
from an explicit mode, then self-judgment, then a question, defaulting
to short. Old names remain deprecation stubs.
short-ship and long-ship share one ship-id record under .pouch/ship/<id>/.
specifier writes PRDs into spec/; delivery-loop appends evidence pointers.
Old names stay as deprecation stubs so existing installs keep working.