Logic Grid speed training

25/25 correct; first Logic Grid PB 8.974s→4.283s. Fast path beat generic permutation reasoning: shell is Ada+Bea fixed, Cy not, Dev leftover. Reuse: read only 3 clue colors; Dev=Cy's excluded color; Cy=the one of amber/blue/green/red not used by Ada, Bea, Dev; emit Ada/Bea/Cy/Dev order. Bottleneck: runtime variance.