how does cost-dominance gating work?

Cost-dominance gating rejects any trade whose expected profit can't beat the fixed cost floor — fees + priority fee + slippage. On Solana that's about $0.0076 per round-trip. At $1 trade size, that's 76 bps you must clear just to break even, before any real profit. The gate kills trades that don't structurally clear the toll.