perf(history): add a transactions revision counter to WalletState

WalletState had no change signal for its transaction list, so a UI
cache had to fingerprint all N transactions every frame to notice an
update. It now carries tx_revision, a counter that only increases;
clear() on disconnect bumps it instead of resetting it, so a cache
built before a reconnect or wallet switch can never match again.

- Every writer of the list bumps it: the full-node refresh, loading the
  cached history, adding, completing and removing a pending send, a
  mining-address relabel, the lite refresh and the screenshot demo
  rows.
- The full-node refresh and the lite refresh (every ~2 s) swap in the
  new list only when it differs field by field, the amount compared
  bit-exactly because -0.0 and +0.0 print differently. An unchanged
  refresh keeps the list and the revision; the compare costs O(N) per
  refresh, not per frame.

Nothing reads the counter yet.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

src/wallet/lite_wallet_controller.cpp

@@ -326,7 +326,9 @@ void applyLiteRefreshModelToWalletState(const LiteWalletAppRefreshModel& model,
     }
 
     if (model.hasTransactions) {
-        state.transactions.clear();
+        // Build aside and swap in only on a real change: this runs every ~2 s, and a bump rebuilds History.
+        std::vector<TransactionInfo> nextTransactions;
+        nextTransactions.reserve(model.transactions.size());
         const int64_t chainHeight =
             model.hasSyncStatus ? static_cast<int64_t>(model.sync.chainHeight) : 0;
         for (const auto& record : model.transactions) {
@@ -356,8 +358,9 @@ void applyLiteRefreshModelToWalletState(const LiteWalletAppRefreshModel& model,
                 const int64_t confs = chainHeight - *record.blockHeight + 1;
                 tx.confirmations = confs > 0 ? static_cast<int>(confs) : 0;
             }
-            state.transactions.push_back(std::move(tx));
+            nextTransactions.push_back(std::move(tx));
         }
+        state.setTransactionsIfChanged(std::move(nextTransactions));
     }
 
     if (model.hasSyncStatus) {