Session-Kontext: Textarea für System-Prompt pro Session

Models/SessionRecord.cs

@@ -9,6 +9,7 @@ public class SessionRecord
     public string Image { get; set; }
     public string AgentId { get; set; }
     public string Workspace { get; set; }
+    public string Context { get; set; }
     public bool IsDeleted { get; set; }
     public string CreatedAt { get; set; }
     public string UpdatedAt { get; set; }