feat: Add CommandTool for user-approved shell command execution, integrating it with a custom spinner that can be paused during interaction.

Program.cs

@@ -239,23 +239,70 @@ while (true)
         }
 
         // Phase 1: Show BouncingBar spinner while agent thinks & invokes tools
-        await AnsiConsole.Status()
-            .Spinner(Spinner.Known.BouncingBar)
-            .SpinnerStyle(Style.Parse("cornflowerblue"))
-            .StartAsync("Thinking...", async ctx =>
+        using var spinnerCts = CancellationTokenSource.CreateLinkedTokenSource(responseCts.Token);
+        bool showSpinner = true;
+        
+        CommandTool.PauseSpinner = () => 
+        { 
+            showSpinner = false; 
+            Console.Write("\r" + new string(' ', 40) + "\r"); 
+        };
+        CommandTool.ResumeSpinner = () => 
+        { 
+            showSpinner = true; 
+        };
+
+        var spinnerTask = Task.Run(async () =>
+        {
+            var frames = Spinner.Known.BouncingBar.Frames;
+            var interval = Spinner.Known.BouncingBar.Interval;
+            int i = 0;
+            
+            // Hide cursor
+            Console.Write("\x1b[?25l");
+            try
             {
-                while (await stream.MoveNextAsync())
+                while (!spinnerCts.Token.IsCancellationRequested)
                 {
-                    responseCts.Token.ThrowIfCancellationRequested();
-                    CaptureUsage(stream.Current);
-                    if (!string.IsNullOrEmpty(stream.Current.Text))
+                    if (showSpinner)
                     {
-                        firstChunk = stream.Current.Text;
-                        fullResponse = firstChunk;
-                        return; // Break out → stops the spinner
+                        var frame = frames[i % frames.Count];
+                        Console.Write($"\r\x1b[38;5;69m{frame}\x1b[0m Thinking...");
+                        i++;
                     }
+                    try { await Task.Delay(interval, spinnerCts.Token); } catch { }
                 }
-            });
+            }
+            finally
+            {
+                // Clear the spinner line and show cursor
+                if (showSpinner)
+                    Console.Write("\r" + new string(' ', 40) + "\r");
+                Console.Write("\x1b[?25h");
+            }
+        });
+
+        try
+        {
+            while (await stream.MoveNextAsync())
+            {
+                responseCts.Token.ThrowIfCancellationRequested();
+                CaptureUsage(stream.Current);
+                if (!string.IsNullOrEmpty(stream.Current.Text))
+                {
+                    firstChunk = stream.Current.Text;
+                    fullResponse = firstChunk;
+                    break;
+                }
+            }
+        }
+        finally
+        {
+            spinnerCts.Cancel();
+            await Task.WhenAny(spinnerTask);
+            CommandTool.PauseSpinner = null;
+            CommandTool.ResumeSpinner = null;
+        }
 
         // Phase 2: Stream text tokens directly to the console
         if (firstChunk != null)