perf: memoize per-frame render hot paths (console, transactions, recent lists)

Immediate-mode render functions re-run every frame; these rebuilt O(N)
state each time even when nothing changed. From a 6-lens perf audit, each
finding verified on a hot-path basis:

- Console: ConsoleModel gains revision(); the full-model filter scan and the
  glyph-by-glyph text-layout pass (BuildConsoleLayout) rebuild only when the
  model / filter / wrap-width / zoom change — previously it re-shaped up to
  10,000 lines every frame even when idle/scrolled. clear() force-invalidates
  the memo mid-render (no OOB on the just-emptied visible set).
- Transactions: the summary-card totals memoize behind the tab's existing
  FNV-1a fingerprint (also folds away a now-duplicate O(N) display-key pass).
- Send / Receive recent lists: early-exit the prefix scan (state.transactions
  is kept newest-first) instead of filtering the whole tx history every frame.
- network_refresh_service: O(new x total) txid find-and-replace -> hash map.
- Sidebar unconfirmed-tx badge cached on last_tx_update + tx count; the
  daemon-memory probe (/proc scan on Linux, popen on macOS) throttled to ~1.5s.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

src/ui/windows/send_tab.cpp

@@ -1120,20 +1120,25 @@ static void RenderRecentSends(const WalletState& state, float width, ImFont* cap
                             S.drawElement("tabs.balance", "recent-tx-icon-size").size * hs);
     ImU32 sendCol = Error();
 
-    // Collect matching transactions
-    std::vector<const TransactionInfo*> sends;
-    for (const auto& tx : state.transactions) {
-        if (tx.type != "send" && tx.type != "shield") continue;
-        sends.push_back(&tx);
-    }
-
     // Grow the list to fill the dead space beneath the (fixed-height) compose card:
     // fit as many newest-first rows as the remaining region can show, instead of a
     // fixed 4. The child scrolls if the real history exceeds what fits, so nothing is
     // lost. A floor of 4 keeps the section substantial when the region is short.
+    // Row budget is hoisted above the collect loop (it only needs the remaining region
+    // height + row height, no per-row state) so the scan can early-exit.
     float listH = std::max(rowH, ImGui::GetContentRegionAvail().y);
     size_t maxRows = std::max<size_t>(4, (size_t)std::floor(listH / rowH));
-    if (sends.size() > maxRows) sends.resize(maxRows);  // newest-first
+
+    // Collect matching transactions. state.transactions is newest-first, so scan only a
+    // bounded prefix and stop once maxRows matches are gathered (mirrors the early-exit in
+    // balance_components.cpp:RenderSharedRecentTx) instead of filtering the whole history.
+    std::vector<const TransactionInfo*> sends;
+    sends.reserve(maxRows);
+    for (const auto& tx : state.transactions) {
+        if (tx.type != "send" && tx.type != "shield") continue;
+        sends.push_back(&tx);
+        if (sends.size() == maxRows) break;  // newest-first: enough rows to fill the region
+    }
 
     ImGui::BeginChild("##RecentSendRows", ImVec2(width, listH), false,
         ImGuiWindowFlags_NoBackground);