StakingJars

struct Jar {
  string name;
  uint256 totalStake;
  uint256 accRewardPerShare;   // 1e18 scaled
  uint256 lastRewardBlock;
  bool active;
}

function stake(uint256 jarId, uint256 amount) external;
function unstake(uint256 jarId, uint256 amount) external;
function claim(uint256 jarId) external;
function pendingReward(uint256 jarId, address staker) external view returns (uint256);

function depositReward(uint256 jarId, uint256 amount) external;
function jarsOf(address staker) external view returns (uint256[] memory);

weight(staker) = stake(staker) × ES(staker)
totalWeight    = Σ weight(s) for all stakers s in jar
share(staker)  = weight(staker) / totalWeight

event Staked(address indexed staker, uint256 indexed jarId, uint256 amount);
event Unstaked(address indexed staker, uint256 indexed jarId, uint256 amount);
event Claimed(address indexed staker, uint256 indexed jarId, uint256 amount);
event RewardDeposited(uint256 indexed jarId, uint256 amount);