Split diagnostic and lifecycle host contracts

engine/Age.Engine/Hosting/IDiagnosticHost.cs

@@ -0,0 +1,11 @@
+namespace Age.Engine.Hosting;
+
+public interface IDiagnosticHost
+{
+    /// <summary>Report a recoverable runtime discrepancy while allowing script execution to continue.</summary>
+    void ReportWarning(string message) => System.Console.Error.WriteLine(message);
+
+    /// <summary>Present a modal diagnostic and return only after the user dismisses it.</summary>
+    void ShowDiagnosticMessage(DiagnosticMessage message)
+        => System.Console.Error.WriteLine($"{message.Caption}: {message.Text}");
+}