fix(telemetry): detach tx.receive and tx.process spans before job hand-off

Both spans are moved into job-queue lambdas and destroyed on a worker
thread. Detaching on the origin thread pops the thread-local OTel Scope
there, so later spans on the peer/RPC thread no longer inherit these as a
leaked ambient parent. Trace_id/parent are unchanged (both are hashSpan).

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

OpenTelemetryPlan/Phase3_taskList.md

@@ -100,6 +100,10 @@
 - Use `SpanGuard::span(TraceCategory::Transactions, "tx", "receive")` factory
   (Phase 1c replaced macros with the SpanGuard factory pattern)
 
+> **Note**: The `tx.receive` guard is `.detached()` before being moved into the
+> `RcvCheckTx` job so its Scope is popped on the peer thread, not leaked to the
+> worker (else later peer messages would inherit this transaction's trace).
+
 **Key modified files**:
 
 - `src/xrpld/overlay/detail/PeerImp.cpp`
@@ -123,6 +127,9 @@
     - Create `tx.process` span
     - Set attributes: `tx_hash`, `tx_type`, `local` (whether from RPC or peer)
     - Record whether sync or async path is taken
+    - `.detached()` the guard before storing it in `TransactionStatus::span`,
+      since it is applied on a batch worker thread — this pops the Scope on the
+      origin thread and stops later work inheriting this transaction's trace
 
   - In `doTransactionAsync()`:
     - Capture parent context before queuing

src/xrpld/app/misc/NetworkOPs.cpp

@@ -1379,7 +1379,11 @@ NetworkOPsImp::processTransaction(
     FailHard failType)
 {
     using namespace telemetry;
-    auto span = std::make_shared<SpanGuard>(txProcessSpan(transaction->getID()));
+    // Detached: this span is stored in TransactionStatus and applied on a
+    // batch worker thread, so it must not leave its Scope bound to this
+    // thread's context stack (that leak would adopt later work into this
+    // transaction's trace).
+    auto span = std::make_shared<SpanGuard>(txProcessSpan(transaction->getID()).detached());
     span->setAttribute(tx_span::attr::txHash, to_string(transaction->getID()).c_str());
     span->setAttribute(tx_span::attr::local, bLocal);
     if (auto const& stx = transaction->getSTransaction())

src/xrpld/overlay/detail/PeerImp.cpp

@@ -1307,7 +1307,10 @@ PeerImp::handleTransaction(
         uint256 const txID = stx->getTransactionID();
 
         using namespace telemetry;
-        auto span = std::make_shared<SpanGuard>(txReceiveSpan(txID, *m));
+        // Detached: this span is handed to a job-queue worker and must not
+        // leave its Scope bound to this peer thread's context stack (that
+        // leak would adopt later peer messages into this transaction's trace).
+        auto span = std::make_shared<SpanGuard>(txReceiveSpan(txID, *m).detached());
         span->setAttribute(tx_span::attr::txHash, to_string(txID).c_str());
         span->setAttribute(tx_span::attr::peerId, static_cast<int64_t>(id_));
         if (auto const* fmt = TxFormats::getInstance().findByType(stx->getTxnType()))