Fr0zka
f5d5a03ad1
Rewrites OPSTACK-HANDOFF.md for a fresh context: the port table, what is left in order, the two things Phase 2 invented that were not in the original design (height space as a second operator family, and IVoxelBiomeField so ops depend on a capability rather than the generator), and the method lessons that cost build cycles to learn. Open items, none blocking: perf (parked by Jahni), C9's library half (no measured risk), VerticalShafts' pessimistic box verdicts, and ClassifyTile still using hand-written guards while ClassifyBox sits verified but unconsumed — which is where the measured tile-skipping would actually become frames. Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>