Define MAG_QUARTER=0, MAG_HALF=1, MAG_FULL=2, NUM_MAGNITUDES=3 in state_layout.cuh. Migrate the one unambiguous semantic comparison in trade_physics.cuh (compute_target_position_4branch magnitude scaling). Arithmetic operations on mag_idx (mag_idx±1, 2-mag_idx, mag_idx<2) are runtime values, not semantic comparisons, and are not migrated. Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>