feat: integrate AI-driven selection panel with context-aware text summarization and quiz generation features.

src/NexusReader.UI.Shared/Services/KnowledgeGraphService.cs

@@ -6,13 +6,17 @@ public sealed class KnowledgeGraphService : IKnowledgeGraphService
 {
     public GraphDataDto? CurrentGraphData { get; private set; }
     public string? ActiveNodeId { get; private set; }
+    public bool IsLoading { get; private set; }
 
     public event Action? OnGraphUpdated;
     public event Action<string>? OnActiveNodeChanged;
+    public event Action<bool>? OnLoadingChanged;
 
     public void UpdateGraph(GraphDataDto newData)
     {
         CurrentGraphData = newData;
+        IsLoading = false;
+        OnLoadingChanged?.Invoke(false);
         OnGraphUpdated?.Invoke();
     }
 
@@ -22,4 +26,18 @@ public sealed class KnowledgeGraphService : IKnowledgeGraphService
         ActiveNodeId = nodeId;
         OnActiveNodeChanged?.Invoke(nodeId);
     }
+
+    public void SetLoading(bool isLoading)
+    {
+        IsLoading = isLoading;
+        OnLoadingChanged?.Invoke(isLoading);
+    }
+
+    public void Clear()
+    {
+        CurrentGraphData = null;
+        ActiveNodeId = null;
+        IsLoading = false;
+        OnGraphUpdated?.Invoke();
+    }
 }