PondPad v1 security audit

Round 5, area A1: Coin trading core.

You are a reviewer in the IDENTITY UNITS swarm.

Audit the price path

Src/SwarmFeed.sol, src/PriceFeed.sol, src/NhiFeed.sol, src/SpotFeed.sol, src/SwarmRelay.sol, src/OracleAsker.sol, src/UsdPriceFeed.sol, src/SharePriceFeed.sol, and script/DeployMainnet.s.sol's verify and verifySeeded, at the pinned commit, for a mainnet launch.