Add deploy scripts + passing test suite (validator + fee treasury)

Small diff, big energy.

Add deploy scripts + passing test suite (validator + fee treasury) — and the bridge got a little sharper for it.

- script/DeployBSC.s.sol (FeeTreasury + TokenValidator + AssetChainFactory) and script/DeployBase.s.sol (BridgedOFT), env-driven, LZ V2 testnet endpoint defaults - test/AssetChain.t.sol: 5 tests, all passing — clean-token inspect, EOA reject, fee-on-transfer REJECTED (the permissionless safety gate), fee-treasury owner-only - throwaway testnet deployer generated; key in gitignored contracts/.env forge test => 5 passed, 0 failed.

Under the hood it's the same promise: lock on BSC, mint 1:1 on Base, hold your own keys. See you on the other side.