SPL Crates (spl-token, spl-associated-token-account)

Rust crates providing client-side and on-chain interfaces for SPL programs. Key crates: `spl-token` (token instructions and state), `spl-associated-token-account` (ATA creation), `spl-memo` (memo instruction), `spl-token-2022` (Token Extensions). These crates provide instruction builders and state deserialization for interacting with SPL programs.