docs(consensus): add MERGE NOTE comments for upstream 86ef16dbeb resolution

Extends merge guidance to cover the empty-disputes bugfix (not yet in
sync-2.5.0): !disputes.empty() guard, stalled() j/clog params,
"should be rare" doc wording, debug→warn promotion, and auto-merged
testDisputes duplicate warning.

src/test/consensus/Consensus_test.cpp

@@ -1131,6 +1131,10 @@ public:
     // MERGE NOTE (sync-2.5.0): upstream adds testDisputes() method and its
     // run() entry here. Keep both all RNG tests below and testDisputes.
     // The stalled() calls in testDisputes need j/clog params (from 86ef16dbeb).
+    // WARNING: upstream testDisputes() body may auto-merge WITHOUT conflict
+    // markers, creating a duplicate alongside our version (which already has
+    // j/clog params). Delete the auto-merged duplicate — keep only the version
+    // with j/clog params and expectStalled() lambda.
     void
     testRngCommitRevealConverges()
     {

src/xrpld/app/consensus/RCLValidations.cpp

@@ -139,6 +139,7 @@ RCLValidationsAdaptor::acquire(LedgerHash const& hash)
 
     if (!ledger)
     {
+        // MERGE NOTE (upstream 86ef16dbeb): promoted from debug to warn.
         JLOG(j_.warn())
             << "Need validated ledger for preferred ledger analysis " << hash;
 

src/xrpld/consensus/Consensus.h

@@ -110,6 +110,8 @@ shouldCloseLedger(
                              last ledger
     @param currentAgreeTime how long, in milliseconds, we've been trying to
                             agree
+    // MERGE NOTE (upstream 86ef16dbeb): "should be rare" wording is from the
+    // bugfix. Upstream sync-2.5.0 has "will cause" instead. Keep ours.
     @param stalled the network appears to be stalled, where
            neither we nor our peers have changed their vote on any disputes in a
            while. This is undesirable, and should be rare, and will cause us to
@@ -2976,6 +2978,10 @@ Consensus<Adaptor>::haveConsensus(
         effectiveParms.ledgerMAX_CONSENSUS = std::chrono::seconds{5};
 
     ConsensusParms const& parms = adaptor_.parms();
+    // MERGE NOTE (upstream 86ef16dbeb): the !result_->disputes.empty() guard,
+    // j_/clog capture in the lambda, and the stalled-logging block below are
+    // all from the bugfix. Upstream sync-2.5.0 does NOT have them yet.
+    // When 86ef16dbeb arrives, keep our version — it's already applied.
     // Stalling is BAD. It means that we have a consensus on the close time, so
     // peers are talking, but we have disputed transactions that peers are
     // unable or unwilling to come to agreement on one way or the other.

src/xrpld/consensus/DisputedTx.h

@@ -175,6 +175,8 @@ public:
         @return bool Whether the peer changed its vote. (A new vote counts as a
        change.)
     */
+    // MERGE NOTE (sync-2.5.0): upstream changes return type from void to
+    // [[nodiscard]] bool. We already have this. Keep ours.
     [[nodiscard]]
     bool
     setVote(NodeID_t const& peer, bool votesYes);