feat(ui): searchable Material Design icon library for lists and folders

src/ClaudeDo.Ui/Converters/IconKeyConverter.cs

@@ -2,27 +2,49 @@ using System.Globalization;
 using Avalonia;
 using Avalonia.Data.Converters;
 using Avalonia.Media;
+using Material.Icons;
 
 namespace ClaudeDo.Ui.Converters;
 
 /// <summary>
-/// Converts an icon key string (e.g. "Sun") to the matching StreamGeometry resource "Icon.Sun".
+/// Converts an icon key to its geometry: "Sun" → the "Icon.Sun" StreamGeometry resource,
+/// "mdi:RocketLaunch" → the Material Design Icons path of that <see cref="MaterialIconKind"/>.
 /// </summary>
 public class IconKeyConverter : IValueConverter
 {
+    /// <summary>Key prefix marking a Material Design Icons kind.</summary>
+    public const string MdiPrefix = "mdi:";
+
     public static IconKeyConverter Instance { get; } = new();
 
+    private static readonly Dictionary<string, Geometry?> MdiCache = new();
+
     public object? Convert(object? value, Type targetType, object? parameter, CultureInfo culture)
     {
         if (value is not string key || string.IsNullOrEmpty(key))
             return null;
 
+        if (key.StartsWith(MdiPrefix, StringComparison.Ordinal))
+            return MdiGeometry(key[MdiPrefix.Length..]);
+
         var resourceKey = $"Icon.{key}";
         if (Application.Current?.TryGetResource(resourceKey, null, out var res) == true)
             return res as StreamGeometry;
         return null;
     }
 
+    /// <summary>Parses (and caches) the geometry for an MDI kind name; null for unknown names.</summary>
+    private static Geometry? MdiGeometry(string name)
+    {
+        if (MdiCache.TryGetValue(name, out var cached))
+            return cached;
+        var geometry = Enum.TryParse<MaterialIconKind>(name, out var kind)
+            ? StreamGeometry.Parse(MaterialIconDataProvider.GetData(kind))
+            : null;
+        MdiCache[name] = geometry;
+        return geometry;
+    }
+
     public object ConvertBack(object? value, Type targetType, object? parameter, CultureInfo culture)
         => throw new NotSupportedException();
 }