Gachapon draws and prize pool

There is no credit currency. The contract stores a fractional draw balance where 1e18 equals one draw; playing one draw consumes one whole draw. totalGachaDrawsEarned accumulates forever and is never consumed.

The pool cap is 10 ETH. The production draw basis is 0.001 ETH, the prize cap cannot be below 1 ETH, and the maximum single reward is 0.5 ETH.

The backend signs a short-lived request containing the user, count, seed, nonce, deadline, and config version. The contract verifies and consumes it, and only ordinary wallet addresses may draw.

Each draw selects a tier and pays from the pool. The balance is updated before payout and the draw path is non-reentrant.