Before: even amina (skill 1) played near-optimal moves because Stockfish
at depth 3 still finds good moves. Blunders just reduced depth to 1 which
barely changes anything in simple positions.

Now:
- Blunder rolls: analyze 5 lines and pick from the worst (3rd-5th best)
- Weak bots (skill <= 5): use MultiPV and randomly pick suboptimal moves
  - Skill 1-2 (amina): NEVER plays the best move, picks from 2nd-5th line
  - Skill 3-5 (tarek): 40% best move, 60% picks from worse options
- Strong bots (skill > 5): unchanged, use standard depth/skill search
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>