Kalshi orderbook fragility: thin liquidity, penny walls, single-order dominance scoring.

Detects thin liquidity, penny walls, spread risk, and fragile orderbook structures in Kalshi markets. Returns 0-100 manipulation-vulnerability score plus signal-level evidence: wide spread (>$0.10), shallow depth (<10 contracts), few price levels, single-order dominance (>80% in top level), penny-wall pattern (large bids at ≤$0.005, common in wash trading). For agents that need to detect fragile order books before placing orders.