fix(telemetry): address clang-tidy errors on phase4 consensus tracing files

- Add [[nodiscard]] to getConsensusTraceStrategy, getYays, getNays
- Add missing <string>, SpanGuard.h, SpanNames.h includes
- Fix widening cast placement (cast before arithmetic, not after)
- Replace nested ternary with lambda for const dir variable
- Add braces to if/else-if chains in Consensus.h
- Concatenate nested namespaces in ConsensusSpanNames.h

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

include/xrpl/telemetry/Telemetry.h

@@ -252,7 +252,7 @@ public:
     shouldTraceLedger() const = 0;
 
     /** @return The configured consensus trace correlation strategy. */
-    virtual std::string const&
+    [[nodiscard]] virtual std::string const&
     getConsensusTraceStrategy() const = 0;
 
 #ifdef XRPL_ENABLE_TELEMETRY

src/libxrpl/telemetry/NullTelemetry.cpp

@@ -18,6 +18,7 @@
 #endif
 
 #include <memory>
+#include <string>
 #include <utility>
 
 namespace xrpl::telemetry {
@@ -87,7 +88,7 @@ public:
         return false;
     }
 
-    std::string const&
+    [[nodiscard]] std::string const&
     getConsensusTraceStrategy() const override
     {
         return setup_.consensusTraceStrategy;

src/tests/libxrpl/telemetry/SpanGuardFactory.cpp

@@ -6,6 +6,7 @@
 #include <cstdint>
 #include <exception>
 #include <stdexcept>
+#include <string>
 #include <utility>
 
 using namespace xrpl;

src/xrpld/app/consensus/RCLConsensus.cpp

@@ -63,6 +63,8 @@
 #include <xrpl/shamap/SHAMapItem.h>
 #include <xrpl/shamap/SHAMapMissingNode.h>
 #include <xrpl/shamap/SHAMapTreeNode.h>
+#include <xrpl/telemetry/SpanGuard.h>
+#include <xrpl/telemetry/SpanNames.h>
 #include <xrpl/telemetry/Telemetry.h>
 #include <xrpl/telemetry/TraceContextPropagator.h>
 
@@ -357,7 +359,7 @@ RCLConsensus::Adaptor::onClose(
         telemetry::cons_span::op::ledgerClose);
     span.setAttribute(
         telemetry::cons_span::attr::ledgerSeq,
-        static_cast<int64_t>(ledger.ledger_->header().seq + 1));
+        static_cast<int64_t>(ledger.ledger_->header().seq) + 1);
     span.setAttribute(telemetry::cons_span::attr::mode, toDisplayString(mode).c_str());
 
     bool const wrongLCL = mode == ConsensusMode::wrongLedger;
@@ -556,7 +558,7 @@ RCLConsensus::Adaptor::doAccept(
         ? acceptSpan->childSpan(telemetry::cons_span::acceptApply)
         : telemetry::SpanGuard::childSpan(telemetry::cons_span::acceptApply, roundSpanContext_);
     doAcceptSpan.setAttribute(
-        telemetry::cons_span::attr::ledgerSeq, static_cast<int64_t>(prevLedger.seq() + 1));
+        telemetry::cons_span::attr::ledgerSeq, static_cast<int64_t>(prevLedger.seq()) + 1);
     doAcceptSpan.setAttribute(
         telemetry::cons_span::attr::closeTime,
         static_cast<int64_t>(consensusCloseTime.time_since_epoch().count()));
@@ -582,9 +584,17 @@ RCLConsensus::Adaptor::doAccept(
         static_cast<int64_t>(rawCloseTimes.peers.size()));
     {
         auto const prevRes = prevLedger.closeTimeResolution();
-        std::string dir = (closeResolution > prevRes) ? "increased"
-            : (closeResolution < prevRes)             ? "decreased"
-                                                      : "unchanged";
+        auto const dir = [&]() -> std::string {
+            if (closeResolution > prevRes)
+            {
+                return "increased";
+            }
+            if (closeResolution < prevRes)
+            {
+                return "decreased";
+            }
+            return "unchanged";
+        }();
         doAcceptSpan.setAttribute(telemetry::cons_span::attr::resolutionDirection, std::move(dir));
     }
 
@@ -1218,10 +1228,10 @@ RCLConsensus::Adaptor::startRoundTracing(RCLCxLedger const& prevLgr)
         return;
 
     roundSpan_->setAttribute(cons_span::attr::ledgerId, to_string(prevLgr.id()).c_str());
-    roundSpan_->setAttribute(cons_span::attr::ledgerSeq, static_cast<int64_t>(prevLgr.seq() + 1));
+    roundSpan_->setAttribute(cons_span::attr::ledgerSeq, static_cast<int64_t>(prevLgr.seq()) + 1);
     roundSpan_->setAttribute(cons_span::attr::mode, toDisplayString(mode_.load()).c_str());
     roundSpan_->setAttribute(cons_span::attr::traceStrategy, strategy.c_str());
-    roundSpan_->setAttribute(cons_span::attr::roundId, static_cast<int64_t>(prevLgr.seq() + 1));
+    roundSpan_->setAttribute(cons_span::attr::roundId, static_cast<int64_t>(prevLgr.seq()) + 1);
 
     roundSpanContext_ = roundSpan_->captureContext();
 }

src/xrpld/consensus/Consensus.h

@@ -1801,11 +1801,17 @@ Consensus<Adaptor>::haveConsensus(std::unique_ptr<std::stringstream> const& clog
 
     char const* stateStr = "no";
     if (result_->state == ConsensusState::Yes)
+    {
         stateStr = "yes";
+    }
     else if (result_->state == ConsensusState::MovedOn)
+    {
         stateStr = "moved_on";
+    }
     else if (result_->state == ConsensusState::Expired)
+    {
         stateStr = "expired";
+    }
     span.setAttribute(cons_span::attr::result, stateStr);
 
     CLOG(clog) << "Consensus has been reached. ";

src/xrpld/consensus/ConsensusSpanNames.h

@@ -78,9 +78,7 @@
 
 #include <xrpl/telemetry/SpanNames.h>
 
-namespace xrpl {
-namespace telemetry {
-namespace cons_span {
+namespace xrpl::telemetry::cons_span {
 
 // ===== Span name segments ====================================================
 
@@ -240,6 +238,4 @@ inline constexpr auto decreased = makeStr("decreased");
 inline constexpr auto unchanged = makeStr("unchanged");
 }  // namespace val
 
-}  // namespace cons_span
-}  // namespace telemetry
-}  // namespace xrpl
+}  // namespace xrpl::telemetry::cons_span

src/xrpld/consensus/DisputedTx.h

@@ -177,14 +177,14 @@ public:
     getJson() const;
 
     //! Number of peers voting yes.
-    int
+    [[nodiscard]] int
     getYays() const
     {
         return yays_;
     }
 
     //! Number of peers voting no.
-    int
+    [[nodiscard]] int
     getNays() const
     {
         return nays_;