Original source: games/001_tidepost/model.py
Original SHA256: b629039d95dc3fb997128912c5abdc73b2a9aa49df0e138a0ee865faec5625ac
Reference: BOARDS[1], contract=3. Only C label is I in teaching map.
Compared traversable positions x 2 tides x 4 delivery masks x 6 inputs with used=7.
Transition count: 1152 PASS
Compared x,y,tide,delivered,used and exact event ordering/result.
