fix(telemetry): use underscore attr names and SpanNames constants in Phase 4

- tempo.yaml: align consensus filter tags with emitted keys
  (consensus_mode, consensus_round, ledger_seq) instead of dotted form
- haveConsensus(): set span attributes before early-return paths so the
  consensus.check span carries diagnostics even when consensus is not reached
- replace hardcoded consensus phase/result/vote literals with
  ConsensusSpanNames.h val constants; add val::phaseOpen/Establish/Accepted
- ConsensusReceiveTracing.h: use canonical consensus::span constants instead
  of duplicate inline detail:: names
- SpanGuardFactory test: use rpc_span / consensus::span constants now that
  levelization permits the dependency

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

.github/scripts/levelization/results/loops.txt

@@ -4,6 +4,9 @@ Loop: test.jtx test.toplevel
 Loop: test.jtx test.unit_test
   test.unit_test ~= test.jtx
 
+Loop: xrpl.telemetry xrpld.consensus
+  xrpld.consensus ~= xrpl.telemetry
+
 Loop: xrpl.telemetry xrpld.rpc
   xrpld.rpc > xrpl.telemetry
 

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

@@ -207,6 +207,8 @@ test.unit_test > xrpl.protocol
 tests.libxrpl > xrpl.basics
 tests.libxrpl > xrpl.config
 tests.libxrpl > xrpl.core
+tests.libxrpl > xrpld.consensus
+tests.libxrpl > xrpld.rpc
 tests.libxrpl > xrpl.json
 tests.libxrpl > xrpl.ledger
 tests.libxrpl > xrpl.net
@@ -253,7 +255,6 @@ xrpl.shamap > xrpl.basics
 xrpl.shamap > xrpl.nodestore
 xrpl.shamap > xrpl.protocol
 xrpl.telemetry > xrpl.config
-xrpl.telemetry > xrpld.consensus
 xrpl.tx > xrpl.basics
 xrpl.tx > xrpl.core
 xrpl.tx > xrpl.ledger
@@ -280,7 +281,6 @@ xrpld.consensus > xrpl.basics
 xrpld.consensus > xrpl.json
 xrpld.consensus > xrpl.ledger
 xrpld.consensus > xrpl.protocol
-xrpld.consensus > xrpl.telemetry
 xrpld.core > xrpl.basics
 xrpld.core > xrpl.config
 xrpld.core > xrpl.core
@@ -332,4 +332,5 @@ xrpld.shamap > xrpld.core
 xrpld.shamap > xrpl.protocol
 xrpld.shamap > xrpl.shamap
 xrpld.telemetry > xrpl.basics
+xrpld.telemetry > xrpld.consensus
 xrpld.telemetry > xrpl.telemetry