Build a BEP-20 staking + reward-vesting contract (Foundry, BNB Chain)

Scope Build a production-ready staking contract for an existing BEP-20 token on BNB Chain. Users stake the token and earn rewards on a configurable rate, with a lockup period and linear vesting on claimed rewards. Requirements - Solidity ^0.8.24, OpenZeppelin 5.x (SafeERC20, ReentrancyGuard, Ownable2Step, Pausable) - Core flows: stake / unstake / claim, with per-user reward accounting (accRewardPerShare pattern) - Configurable reward rate + lockup; owner-settable, with an emergency-withdraw guarded by Pausable - No proxies/upgradeability needed — immutable deploy is fine - Gas-conscious (optimizer 200 runs), NatSpec on all external/public functions Deliverables - Foundry repo: contract + interfaces - Test suite ≥90% coverage, including fuzz tests on the reward math and re-entrancy checks - Deploy script (script/*.s.sol) + BscScan verification steps - Short README: constructor params, admin flows, and known assumptions References - Token: standard BEP-20, 18 decimals, fixed supply (no mint/burn hooks) - Target: BNB Chain; reuse OpenZeppelin wherever possible Deadline: 7 days from assignment. Please quote a fixed price and delivery time.