Adds a gen_seeds binary to solitaire_assetgen that brute-searches seeds
for hands solvable in ≤250 moves, then writes the list. The 75 new
seeds (0xCAFEBABE prefix) are appended to CHALLENGE_SEEDS in
solitaire_data::challenge.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
funman300