chore: change stale agent colour to yellow (#34)

On the Mac app, we use Yellow when an agent's last handshake was longer
than 5 minutes ago. We should reserve red for a more fatal error, rather
than something that will show on every connection.

Author: ethanndickson

App/Converters/AgentStatusToColorConverter.cs

@@ -9,6 +9,7 @@ namespace Coder.Desktop.App.Converters;
 public class AgentStatusToColorConverter : IValueConverter
 {
     private static readonly SolidColorBrush Green = new(Color.FromArgb(255, 52, 199, 89));
+    private static readonly SolidColorBrush Yellow = new(Color.FromArgb(255, 204, 1, 0));
     private static readonly SolidColorBrush Red = new(Color.FromArgb(255, 255, 59, 48));
     private static readonly SolidColorBrush Gray = new(Color.FromArgb(255, 142, 142, 147));
 
@@ -19,6 +20,7 @@ public object Convert(object value, Type targetType, object parameter, string la
         return status switch
         {
             AgentConnectionStatus.Green => Green,
+            AgentConnectionStatus.Yellow => Yellow,
             AgentConnectionStatus.Red => Red,
             _ => Gray,
         };

App/ViewModels/AgentViewModel.cs

@@ -9,6 +9,7 @@ namespace Coder.Desktop.App.ViewModels;
 public enum AgentConnectionStatus
 {
     Green,
+    Yellow,
     Red,
     Gray,
 }

App/ViewModels/TrayWindowViewModel.cs

@@ -137,7 +137,7 @@ private void UpdateFromRpcModel(RpcModel rpcModel)
                 HostnameSuffix = fqdnSuffix,
                 ConnectionStatus = lastHandshakeAgo < TimeSpan.FromMinutes(5)
                     ? AgentConnectionStatus.Green
-                    : AgentConnectionStatus.Red,
+                    : AgentConnectionStatus.Yellow,
                 DashboardUrl = WorkspaceUri(coderUri, workspace?.Name),
             });
         }