Add Batch feature (XLS-56) (#5060)

- 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`).

src/test/jtx/impl/acctdelete.cpp

@@ -17,6 +17,7 @@
 */
 //==============================================================================
 
+#include <test/jtx/Env.h>
 #include <test/jtx/acctdelete.h>
 
 #include <xrpl/protocol/jss.h>
@@ -36,6 +37,28 @@ acctdelete(jtx::Account const& account, jtx::Account const& dest)
     return jv;
 }
 
+// Close the ledger until the ledger sequence is large enough to close
+// the account.  If margin is specified, close the ledger so `margin`
+// more closes are needed
+void
+incLgrSeqForAccDel(jtx::Env& env, jtx::Account const& acc, std::uint32_t margin)
+{
+    using namespace jtx;
+    auto openLedgerSeq = [](jtx::Env& env) -> std::uint32_t {
+        return env.current()->seq();
+    };
+
+    int const delta = [&]() -> int {
+        if (env.seq(acc) + 255 > openLedgerSeq(env))
+            return env.seq(acc) - openLedgerSeq(env) + 255 - margin;
+        return 0;
+    }();
+    env.test.BEAST_EXPECT(margin == 0 || delta >= 0);
+    for (int i = 0; i < delta; ++i)
+        env.close();
+    env.test.BEAST_EXPECT(openLedgerSeq(env) == env.seq(acc) + 255 - margin);
+}
+
 }  // namespace jtx
 }  // namespace test
 }  // namespace ripple