Fix Windows channel tree ordering

clients/windows/VoiceCat.Windows/Administration.cs

@@ -24,7 +24,7 @@ public sealed partial class VoiceCatClient
     }
     private static Voicecat.V1.Channel Channel(ChannelEditInfo info) => new()
     {
-        Id = info.Id, ParentId = info.ParentId, Name = info.Name, Topic = info.Topic, MaxUsers = info.MaxUsers, Order = unchecked((int)info.SortOrder),
+        Id = info.Id, ParentId = info.ParentId, Name = info.Name, Topic = info.Topic, MaxUsers = info.MaxUsers, Order = info.SortOrder,
         Audio = new() { Codec = info.Audio.Codec, Mode = info.Audio.Stereo ? ChannelMode.ModeStereo : ChannelMode.ModeMono, SampleRate = info.Audio.SampleRate,
             BitrateBps = info.Audio.BitrateBps, FrameMs = info.Audio.FrameMs, Application = (OpusApplication)info.Audio.Application, Complexity = info.Audio.Complexity,
             Fec = info.Audio.Fec, ExpectedPacketLoss = info.Audio.ExpectedPacketLoss, Dtx = info.Audio.Dtx, Dred = info.Audio.Dred }

clients/windows/VoiceCat.Windows/ChannelHierarchy.cs

@@ -0,0 +1,32 @@
+namespace VoiceCat.Windows;
+
+/// <summary>A channel and its ordered children as displayed by the Windows client.</summary>
+public sealed record ChannelHierarchyItem(
+    ChannelInfo Channel,
+    IReadOnlyList<ChannelHierarchyItem> Children);
+
+public static class ChannelHierarchy
+{
+    /// <summary>
+    /// Builds the server-defined channel hierarchy. SortOrder orders siblings; LINQ's stable
+    /// ordering preserves the server's sequence when siblings have the same value.
+    /// </summary>
+    public static IReadOnlyList<ChannelHierarchyItem> Build(IReadOnlyList<ChannelInfo> channels)
+    {
+        var byParent = channels
+            .GroupBy(channel => channel.ParentId)
+            .ToDictionary(group => group.Key, group => group.OrderBy(channel => channel.SortOrder).ToArray());
+
+        IReadOnlyList<ChannelHierarchyItem> AddChildren(uint parentId)
+        {
+            if (!byParent.TryGetValue(parentId, out ChannelInfo[]? children))
+                return [];
+
+            return children
+                .Select(channel => new ChannelHierarchyItem(channel, AddChildren(channel.Id)))
+                .ToArray();
+        }
+
+        return AddChildren(0);
+    }
+}

clients/windows/VoiceCat.Windows/Models.cs

@@ -8,7 +8,7 @@ public sealed record ChannelInfo(
     string Topic,
     bool PasswordProtected,
     uint MaxUsers,
-    uint SortOrder,
+    int SortOrder,
     AudioConfigInfo Audio);
 
 public sealed record ChannelEditInfo(
@@ -19,7 +19,7 @@ public sealed record ChannelEditInfo(
     bool PasswordProtected,
     string? Password,
     uint MaxUsers,
-    uint SortOrder,
+    int SortOrder,
     AudioConfigInfo Audio);
 
 public sealed record UserInfo(

clients/windows/VoiceCat.Windows/VoiceCatClient.cs

@@ -172,7 +172,7 @@ public sealed partial class VoiceCatClient : IDisposable
     }
     public VcResult LeaveVoice() { StopDevices(); local.Clear(); return Request(new() { UnsubscribeVoice = new() }); }
 
-    public List<ChannelInfo> ListChannels() => core.Channels.Select(c => new ChannelInfo(c.Id, c.ParentId, c.Name, c.Topic, c.PasswordProtected, c.MaxUsers, unchecked((uint)c.Order), Audio(c.Audio))).ToList();
+    public List<ChannelInfo> ListChannels() => core.Channels.Select(c => new ChannelInfo(c.Id, c.ParentId, c.Name, c.Topic, c.PasswordProtected, c.MaxUsers, c.Order, Audio(c.Audio))).ToList();
     public List<UserInfo> ListUsers() => core.Users.Select(u => new UserInfo(u.Id, u.Nickname, u.IsGuest, u.ChannelId, u.SelfMicMuted, u.SelfDeafened, u.ServerMuted, u.ServerDeafened, u.VoiceSubscribed)).ToList();
     public List<StreamSummary> ListUserStreams(uint id) => id == core.Authentication?.Self.Id
         ? local.Values.Select(s => new StreamSummary(s.Alias, (VcStreamKind)s.Info.Kind, s.Info.Label)).ToList()