fix(centralui): bound FlowDebugService script cache (review 2026-10-21 07/M-2)

src/ZB.MOM.WW.ScadaBridge.CentralUI/Services/FlowDebugService.cs

@@ -107,6 +107,13 @@ public sealed class FlowDebugService : IFlowDebugService
     /// </summary>
     private readonly Dictionary<int, InstanceScripts> _scriptCache = new();
 
+    /// <summary>
+    /// Ceiling on <see cref="_scriptCache"/> entries (review 2026-10-21 07/M-2). Only the most
+    /// recently selected instance is ever read back, so a small bound loses nothing; reaching it
+    /// drops the whole cache before the new entry goes in.
+    /// </summary>
+    internal const int ScriptCacheCapacity = 8;
+
     /// <summary>One instance's flattened scripts: the unique name the site keys on, the raw resolved scripts, and the picker projection.</summary>
     private sealed record InstanceScripts(
         string UniqueName,
@@ -484,6 +491,10 @@ public sealed class FlowDebugService : IFlowDebugService
             .ToList();
 
         var loaded = new InstanceScripts(instance.UniqueName, scripts, options);
+        if (_scriptCache.Count >= ScriptCacheCapacity && !_scriptCache.ContainsKey(instanceId))
+        {
+            _scriptCache.Clear();
+        }
         _scriptCache[instanceId] = loaded;
         return loaded;
     }