feat(telemetry): complete Phase 4 consensus tracing

Implement remaining Phase 4/4a consensus tracing tasks:

- Add consensus.phase.open span (open → closeLedger lifecycle)
- Add consensus.proposal.receive span in PeerImp with trusted attr
- Add consensus.validation.receive span in PeerImp with trusted/seq attrs
- Add tx_count attr on accept.apply, disputes_count on update_positions
- Add tx.included events with txId in doAccept transaction loop
- Enhance dispute.resolve event with yays/nays fields
- Add avalanche_threshold attr on update_positions span
- Reparent accept/accept.apply as children of round span via childSpan()

Also adds compile-time constants in ConsensusSpanNames.h and updates
the span hierarchy diagram.

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

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

@@ -7,6 +7,9 @@ Loop: test.jtx test.unit_test
 Loop: xrpl.telemetry xrpld.rpc
   xrpld.rpc > xrpl.telemetry
 
+Loop: xrpld.app xrpld.consensus
+  xrpld.app > xrpld.consensus
+
 Loop: xrpld.app xrpld.overlay
   xrpld.app > xrpld.overlay
 

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

@@ -101,7 +101,6 @@ test.core > xrpl.server
 test.csf > xrpl.basics
 test.csf > xrpld.consensus
 test.csf > xrpl.json
-test.csf > xrpl.telemetry
 test.csf > xrpl.ledger
 test.csf > xrpl.protocol
 test.json > test.jtx
@@ -196,7 +195,6 @@ tests.libxrpl > xrpl.net
 tests.libxrpl > xrpl.protocol
 tests.libxrpl > xrpl.protocol_autogen
 tests.libxrpl > xrpl.telemetry
-tests.libxrpl > xrpld.telemetry
 xrpl.conditions > xrpl.basics
 xrpl.conditions > xrpl.protocol
 xrpl.core > xrpl.basics
@@ -238,7 +236,6 @@ xrpl.tx > xrpl.protocol
 xrpld.app > test.unit_test
 xrpld.app > xrpl.basics
 xrpld.app > xrpl.core
-xrpld.app > xrpld.consensus
 xrpld.app > xrpld.core
 xrpld.app > xrpl.json
 xrpld.app > xrpl.ledger
@@ -256,7 +253,6 @@ xrpld.consensus > xrpl.json
 xrpld.consensus > xrpl.ledger
 xrpld.consensus > xrpl.protocol
 xrpld.consensus > xrpl.telemetry
-xrpld.consensus > xrpld.telemetry
 xrpld.core > xrpl.basics
 xrpld.core > xrpl.core
 xrpld.core > xrpl.net