fix(ui): add vertical padding above and below the recent-alerts popup content

The alert-history popup content sat flush against the popup's top and bottom edges. Add a
padY spacer above the header and below the content (on both the empty and populated paths).

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

src/app.cpp

@@ -2293,10 +2293,13 @@ void App::renderAlertHistoryPanel()
     const auto& hist = notes.history();
     const float innerW = ImGui::GetContentRegionAvail().x;
     const float padX = 8.0f * dp;
+    const float padY = 8.0f * dp;
 
     ImFont* icoF = m::Type().iconSmall();
     ImFont* txtF = m::Type().caption();
 
+    ImGui::Dummy(ImVec2(0.0f, padY));  // breathing room above the content
+
     // Header: "Recent alerts" on the left, a Clear-all icon button on the right.
     ImGui::SetCursorPosX(padX);
     ImGui::PushFont(txtF);
@@ -2325,6 +2328,7 @@ void App::renderAlertHistoryPanel()
         ImGui::PushFont(txtF);
         ImGui::TextDisabled("%s", TR("alerts_none"));
         ImGui::PopFont();
+        ImGui::Dummy(ImVec2(0.0f, padY));  // breathing room below the content
         return;
     }
 
@@ -2369,6 +2373,7 @@ void App::renderAlertHistoryPanel()
         ImGui::Spacing();
     }
     ImGui::EndChild();
+    ImGui::Dummy(ImVec2(0.0f, padY));  // breathing room below the content
 }
 
 void App::renderStatusBar()