Adds S as the twenty-second card letter and SUBMANIFEST as the ninth artifact type, per draft-fossil-submanifests-00 sections 3 and 4. Type determination reassigns after the card scan rather than during it, so no type is committed while cards are still being read (section 9.1). Reading and classification only: no tree walk, no emission.

The draft's seven appendix vectors ship alongside, each named by the SHA3-256 the draft states and checked by a test that recomputes it. check-in: 9b8bad477a user: dmestas tags: sub-manifest