feat(ui): add colored dot brush to ListItemViewModel

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

src/ClaudeDo.Ui/ViewModels/ListItemViewModel.cs

@@ -1,3 +1,5 @@
+using System;
+using Avalonia.Media;
 using ClaudeDo.Data.Models;
 using CommunityToolkit.Mvvm.ComponentModel;
 
@@ -9,6 +11,17 @@ public partial class ListItemViewModel : ViewModelBase
     [ObservableProperty] private string? _workingDir;
     [ObservableProperty] private string _defaultCommitType;
 
+    private static readonly IBrush[] DotPalette =
+    [
+        new SolidColorBrush(Color.Parse("#3d9474")), // green
+        new SolidColorBrush(Color.Parse("#5571a1")), // blue
+        new SolidColorBrush(Color.Parse("#d4964a")), // amber
+        new SolidColorBrush(Color.Parse("#7c6aad")), // purple
+        new SolidColorBrush(Color.Parse("#c25d6a")), // rose
+    ];
+
+    public IBrush DotBrush => DotPalette[Math.Abs(Id.GetHashCode()) % DotPalette.Length];
+
     public string Id { get; }
 
     public ListItemViewModel(ListEntity entity)