UNRENT #1505

Reclaims overpaid rent from Solana token accounts. SIMD-0437 lowers lamports_per_byte from 6,960 to 696 in five steps; existing accounts keep their old deposit until it is withdrawn. UNRENT scans a wallet and builds unsigned reclaim transactions (WithdrawExcessLamports, CloseAccount) for the wallet to sign. Non-custodial, no API key.