- Specification: [XRPLF/XRPL-Standards 56](https://github.com/XRPLF/XRPL-Standards/blob/master/XLS-0056d-batch/README.md)
- Amendment: `Batch`
- Implements execution of multiple transactions within a single batch transaction with four execution modes: `tfAllOrNothing`, `tfOnlyOne`, `tfUntilFailure`, and `tfIndependent`.
- Enables atomic multi-party transactions where multiple accounts can participate in a single batch, with up to 8 inner transactions and 8 batch signers per batch transaction.
- Inner transactions use `tfInnerBatchTxn` flag with zero fees, no signature, and empty signing public key.
- Inner transactions are applied after the outer batch succeeds via the `applyBatchTransactions` function in apply.cpp.
- Network layer prevents relay of transactions with `tfInnerBatchTxn` flag - each peer applies inner transactions locally from the batch.
- Batch transactions are excluded from AccountDelegate permissions but inner transactions retain full delegation support.
- Metadata includes `ParentBatchID` linking inner transactions to their containing batch for traceability and auditing.
- Extended STTx with batch-specific signature verification methods and added protocol structures (`sfRawTransactions`, `sfBatchSigners`).
This change implements the account permission delegation described in XLS-75d, see https://github.com/XRPLF/XRPL-Standards/pull/257.
* Introduces transaction-level and granular permissions that can be delegated to other accounts.
* Adds `DelegateSet` transaction to grant specified permissions to another account.
* Adds `ltDelegate` ledger object to maintain the permission list for delegating/delegated account pair.
* Adds an optional `Delegate` field in common fields, allowing a delegated account to send transactions on behalf of the delegating account within the granted permission scope. The `Account` field remains the delegating account; the `Delegate` field specifies the delegated account. The transaction is signed by the delegated account.
