feat: Experimental: Add more specific error messages in submit/simulate

[mvadari]

High Level Overview of Change

This PR refactors the error code return spots to add the log line in that shows up there, which can be returned in submit/simulate for easier debug

This is an experimental vibe-coded version for PoC purposes

Sample output:

Request:
{
  "command": "simulate",
  "tx_json": {
    "TransactionType": "SignerListSet",
    "Account": "rHb9CJAWyB4rj91VRWn96DkukG4bwdtyTh",
    "SignerEntries": [],
    "SignerQuorum": 1
  }
}

Response:
{
  "api_version": 2,
  "id": 5,
  "result": {
    "applied": false,
    "engine_result": "temMALFORMED",
    "engine_result_code": -299,
    "engine_result_message": "Malformed transaction.",
    "engine_result_reason": "Too many or too few signers in signer list.",   <--- NEW ADDITION TO OUTPUT
    "ledger_index": 3,
    "tx_json": {
      "Account": "rHb9CJAWyB4rj91VRWn96DkukG4bwdtyTh",
      "Fee": "10",
      "Sequence": 1,
      "SignerEntries": [],
      "SignerQuorum": 1,
      "SigningPubKey": "",
      "TransactionType": "SignerListSet",
      "TxnSignature": "",
      "hash": "19F6B0D9FFC68164A011161A00477EA1FF173A31FF5095B1B72FA8270294A547"
    }
  },
  "type": "response"
}

Context of Change

easier debugging

API Impact

• Public API: New feature (new methods and/or new fields)
• Public API: Breaking change (in general, breaking changes should only impact the next api_version)
• libxrpl change (any change that may affect libxrpl or dependents of libxrpl)
• Peer protocol change (must be backward compatible or bump the peer protocol version)

[codecov]

Codecov Report

❌ Patch coverage is 88.27160% with 38 lines in your changes missing coverage. Please review.

Files with missing lines	Patch %	Lines
src/libxrpl/tx/transactors/payment/Payment.cpp	44.4%	5 Missing ⚠️
src/libxrpl/tx/transactors/system/Change.cpp	64.3%	5 Missing ⚠️
src/libxrpl/tx/Transactor.cpp	81.0%	4 Missing ⚠️
src/libxrpl/tx/paths/MPTEndpointStep.cpp	0.0%	4 Missing ⚠️
...c/libxrpl/tx/transactors/lending/LoanBrokerSet.cpp	71.4%	2 Missing ⚠️
src/libxrpl/tx/transactors/lending/LoanSet.cpp	86.7%	2 Missing ⚠️
src/libxrpl/tx/transactors/token/TrustSet.cpp	66.7%	2 Missing ⚠️
src/libxrpl/tx/transactors/vault/VaultDelete.cpp	60.0%	2 Missing ⚠️
include/xrpl/tx/paths/detail/Steps.h	0.0%	1 Missing ⚠️
src/libxrpl/tx/paths/DirectStep.cpp	50.0%	1 Missing ⚠️
... and 10 more

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