True when chain is a grammatically valid CAIP-2 id in the solana
namespace (any reference). Used to gate payment-request URLs and to
filter derivation paths per chain (v1.2 §2.2 — index spaces are
chain-scoped, the caller filters by subjectWalletChain first).
True when
chainis a grammatically valid CAIP-2 id in thesolananamespace (any reference). Used to gate payment-request URLs and to filter derivation paths per chain (v1.2 §2.2 — index spaces are chain-scoped, the caller filters bysubjectWalletChainfirst).