feat: add WalletInitialization, tokenEnablements, stakingAuthorize, and optional lamportsPerSignature

- Detect CreateAccount + NonceInitialize pattern as WalletInitialization
- Add tokenEnablements (ATA address + mint address) to ExplainedTransaction
- Add StakingAuthorizeInfo to ExplainedTransaction for staking authority changes
- lamportsPerSignature defaults to 5000 (Solana protocol constant) when
  not provided, simplifying the API for consumers
- Export StakingAuthorizeInfo type from the public API

BTC-3025

Author: lcovar