URC-3 Standardizes Uniswap v4 Hook TVL Reporting

Uniswap v4 hooks get IHookStats standard for TVL and effective liquidity reporting. Interface adds getReserves, getEffectiveLiquidity, hook functions. Targets custom-accounting hooks with external venues, vaults, rehypothecation. ERC-165 required. Routers use effective liquidity for scoring, not binding quotes. Status: Discussion.