refactor: 插件窗体由 static 单例状态改为实例字段（对齐 TextViewer）

将 10 个 CycleGUI 窗体/管理器从进程级 static 单例状态改为实例字段 + 实例方法，
消除本地端/Web 端共享同一可变状态的隐患（对齐 TextViewer 正例）。

每个类保留一个 private static _instance 单实例持有者；静态入口 Open()/OpenViewer()
与实例 Show() 均转发到该实例，调用方零改动、单实例“置前”行为不变。

涉及：ChargeStationManagementForm、ChargeStrategyConfigForm、CommunicationMonitorForm、
AlarmConfigManagementForm、ButtonBoxManager、DoorManager、DoorMonitor、
LoopViewer、DeliveryViewer、TrafficInterlockViewer。

构建：dotnet build StandardScene.sln --no-incremental → 0 错误，30 警告（与基线一致，无新增）。

StandardScene.Core/InterLock/TrafficInterlockViewer.cs

@@ -25,29 +25,33 @@ namespace LoopViewerApp
     {
         private const string TableId = "traffic-area-list";
 
-        private static string JsonPath =>
+        private string JsonPath =>
             Path.Combine(AppDomain.CurrentDomain.BaseDirectory, "Config", "traffic.json");
 
-        private static readonly object SaveLock = new object();
+        private readonly object SaveLock = new object();
 
-        private static Panel _panel;
-        private static string _editingAreaId = "";
-        private static readonly HashSet<string> _selected = new HashSet<string>(StringComparer.Ordinal);
+        private Panel _panel;
+        private string _editingAreaId = "";
+        private readonly HashSet<string> _selected = new HashSet<string>(StringComparer.Ordinal);
 
-        private static string _areaName = "";
-        private static string _stationIds = "";
-        private static string _controlRight = "";
-        private static bool _isOccupied;
-        private static bool _isEnabled = true;
-        private static string _editingHint = "新增区域";
-        private static string _editErr = "";
-        private static volatile string _status = "";
+        private string _areaName = "";
+        private string _stationIds = "";
+        private string _controlRight = "";
+        private bool _isOccupied;
+        private bool _isEnabled = true;
+        private string _editingHint = "新增区域";
+        private string _editErr = "";
+        private volatile string _status = "";
 
         /// <summary>打开（或置前）区域管理面板。兼容原 <c>new TrafficInterlockViewer().Show()</c> 调用方式。</summary>
         public void Show() => Open();
 
         /// <summary>打开（或置前）区域管理面板。</summary>
-        public static void Open()
+        public static void Open() => (_instance ??= new TrafficInterlockViewer()).OpenCore();
+
+        private static TrafficInterlockViewer _instance;
+
+        private void OpenCore()
         {
             if (_panel != null)
             {
@@ -171,7 +175,7 @@ namespace LoopViewerApp
             });
         }
 
-        private static void ConfirmDeleteSelected()
+        private void ConfirmDeleteSelected()
         {
             if (_selected.Count == 0)
             {
@@ -187,7 +191,7 @@ namespace LoopViewerApp
             CycleUiHelper.ConfirmThen(prompt, DeleteSelected);
         }
 
-        private static void DeleteSelected()
+        private void DeleteSelected()
         {
             var selectedIds = _selected.ToHashSet(StringComparer.Ordinal);
             var removed = 0;
@@ -203,7 +207,7 @@ namespace LoopViewerApp
             _panel?.Repaint();
         }
 
-        private static void SaveArea()
+        private void SaveArea()
         {
             try
             {
@@ -270,7 +274,7 @@ namespace LoopViewerApp
             }
         }
 
-        private static void LoadAreaToFields(TrafficArea a)
+        private void LoadAreaToFields(TrafficArea a)
         {
             if (a == null) return;
             _editingHint = $"编辑：{a.AreaName}";
@@ -284,7 +288,7 @@ namespace LoopViewerApp
             _editErr = "";
         }
 
-        private static void ClearPanelInputs()
+        private void ClearPanelInputs()
         {
             _editingAreaId = "";
             _editingHint = "新增区域";
@@ -296,7 +300,7 @@ namespace LoopViewerApp
             _editErr = "";
         }
 
-        private static void SaveToConfig()
+        private void SaveToConfig()
         {
             string json;
             try
@@ -331,7 +335,7 @@ namespace LoopViewerApp
         }
 
         /// <summary>解析站点集合字符串，如 "1,2,3" → <see cref="List{T}"/> of int。</summary>
-        private static List<int> ParseStationIds(string text)
+        private List<int> ParseStationIds(string text)
         {
             var list = new List<int>();
             if (string.IsNullOrWhiteSpace(text)) return list;
@@ -343,19 +347,19 @@ namespace LoopViewerApp
             return list;
         }
 
-        private static void EnsureAreaIdsLocked()
+        private void EnsureAreaIdsLocked()
         {
             foreach (var area in TrafficInterlockMission.TrafficAreaList)
                 EnsureAreaId(area);
         }
 
-        private static string EnsureAreaId(TrafficArea area)
+        private string EnsureAreaId(TrafficArea area)
         {
             if (string.IsNullOrWhiteSpace(area.Id))
                 area.Id = NewAreaId();
             return area.Id;
         }
 
-        private static string NewAreaId() => Guid.NewGuid().ToString("N");
+        private string NewAreaId() => Guid.NewGuid().ToString("N");
     }
 }