zkfair proposal voting:

[tsexiao]

zkfair proposal voting:

1. Add swap function and add usdc/zkf
   eth/zkf
   usdt/zkf
   zkf single currency pledge and other liquidity
2. Enable the function of inviting new users. Each invited user will receive 2-5% of the transaction rebate from the invited user. The rebate will be distributed in the form of zkf single currency.