Merge upstream/ripple/smart-escrow into xrplf/smart-contracts

Upstream rewrote the wasm VM and host-function system (Rust `crates/`
bridged via cxx), collapsed `transactions.macro` onto `TxSettings`, and
moved invariant running from `ApplyContext` to `Transactor`. This merge
resolves those conflicts and the breaks that carried no conflict marker.

Conflict resolutions of note:
- transactions.macro: took upstream's 5-argument `TxSettings` form and
  re-expressed our `emitable` column as `TxSettings::emittance`, a new
  scoped `Emittance` enum in TxSettings.h. `Emitable.cpp` and the
  transaction code generator read the new member.
- sfields.macro: upstream claimed UINT32 75-80, so `sfParameterFlag`
  moves from 80 to 86. The amendment is not live, so no wire break.
- HostFunc.h: took upstream's version, which drops `floatRoot`, and
  re-added the 15 contract virtuals. `setDataNestedObjectField`'s
  parameters are renamed to `(account, key, nestedKey, value)` to match
  the implementation; the wire order is unchanged.
- WasmCommon.h: `SubmitTxnFailure` (-21) and `InvalidState` (-22) join
  upstream's enum and the Rust `host_errors!` table. `Success` is gone;
  the helpers that compared against it now return `expected<void, ...>`.
- Transactor.cpp: kept the emitted-transaction pass, now using
  `checkInvariants(result, fee, InvariantScope::ProtocolOnly)`.

Breaks with no conflict marker:
- `Emitable.cpp` used the 8-argument TRANSACTION macro.
- `STTx::getSeqValue` is gone; use `getSeqProxy().value()`.
- `NetworkOPsImp::subLock_` is now `streamLock_`, held with `scoped_lock`.
- The `LedgerEntryHelpers` namespace is now `ledger_entry_helpers`.
- `keylet::vault` takes a `SeqProxy`. The three contract `ledger_entry`
  parsers were copy-pasted from the vault one and returned vault keylets;
  they now build contract, contract source and contract data keylets from
  their own fields. `contract_hash` is added to jss.

The 15 contract host functions still register through the deleted C++
wrapper layer, so contract bytecode does not run yet. Porting them to the
Rust-declared ABI is the next commit.

.github/scripts/levelization/results/ordering.txt

@@ -1,6 +1,9 @@
 benchmarks.libxrpl > xrpl.basics
 benchmarks.libxrpl > xrpl.config
 benchmarks.libxrpl > xrpl.nodestore
+benchmarks.libxrpl > xrpl.protocol
+benchmarks.libxrpl > xrpl.protocol_autogen
+benchmarks.libxrpl > xrpl.tx
 libxrpl.basics > xrpl.basics
 libxrpl.conditions > xrpl.basics
 libxrpl.conditions > xrpl.conditions