Staking Reward Calculator

Probes the naming conventions that widely-copied staking contracts use — balanceOf, stakedOf, userInfo for the position, and earned, pendingReward, claimable for rewards — and reports which one answered rather than assuming a design. From the reward rate and total staked it works out your share of the pool and what that pays per day and per thirty days. Rewards are given in tokens rather than as an APY on purpose: turning them into a percentage needs a price for both the staked token and the reward token, neither is available on chain here, and inventing one would be worse than leaving it out. A finished reward period is flagged prominently, since a position left staked there is earning nothing at all.