0210c14858
PCG32 seeded RNG; immutable 8x8 GridState with occupancy bitmask; placement legality + anyPlacementExists; simultaneous row/col clears with single-count gem credit; combo scoring with one-move grace; weighted-bag generator with pity bias and depth-3 solvability nudge. All TDD, 51 tests green. Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>