feat(message-list): wire ChunkRenderer ctor + AttachPayloadHandler setter

H integrates the chunk-render pipeline into MessageList:

- Extends ctor to 4 params (themes, resolver, fonts, chunkRenderer);
  TokenResolver preserved as load-bearing dep
- Adds private PayloadHandler? _handler field + internal
  AttachPayloadHandler(PayloadHandler) setter
- Switches DrawCompactRow/DrawCardRow render-path to
  _chunkRenderer.DrawChunks(message.Content, wrap, handler, 0f)
  instead of plain TextUnformatted

Setter-injection for PayloadHandler is the §6.2 cycle-resolution
(PayloadHandler → MainWindow → MessageList → PayloadHandler ctor-cycle
broken by post-construction wiring). G's HostedService.StartAsync will
call AttachPayloadHandler after both singletons resolve.

Also extends MessageList DI-reg in PluginHostFactory.cs with the
ChunkRenderer arg (4th GetRequiredService).

HellionChat/PluginHostFactory.cs

@@ -132,7 +132,8 @@ internal static class PluginHostFactory
         services.AddSingleton(sp => new Ui.Components.MessageList(
             sp.GetRequiredService<ThemeRegistry>(),
             sp.GetRequiredService<Ui.StyleEngine.TokenResolver>(),
-            sp.GetRequiredService<FontManager>()
+            sp.GetRequiredService<FontManager>(),
+            sp.GetRequiredService<Ui.Components.ChunkRenderer>()
         ));
         services.AddSingleton(_ => new Ui.Components.SymbolPicker());
         services.AddSingleton(sp => new Ui.Components.InputBar(

HellionChat/Ui/Components/MessageList.cs

@@ -12,8 +12,7 @@ namespace HellionChat.Ui.Components;
 // rows have a constant line height; card mode falls back to a linear
 // render with a per-message height cache and an IsItemVisible skip path
 // so off-screen rows place a Dummy of the cached height rather than
-// running the full render again. Text-only rendering for now — full
+// running the full render again.
-// chunk/payload rendering re-attaches in a later cycle.
 internal sealed class MessageList
 {
     private const float CompactRowHeight = 18f;
@@ -21,12 +20,28 @@ internal sealed class MessageList
     private readonly ThemeRegistry _themes;
     private readonly TokenResolver _resolver;
     private readonly FontManager _fonts;
+    private readonly ChunkRenderer _chunkRenderer;
 
-    public MessageList(ThemeRegistry themes, TokenResolver resolver, FontManager fonts)
+    private PayloadHandler? _handler;
+
+    // §6.2: setter-injection breaks the PayloadHandler → MainWindow → MessageList → PayloadHandler 3-cycle.
+    // Wired by PayloadHandlerInitHostedService.StartAsync after both singletons exist.
+    internal void AttachPayloadHandler(PayloadHandler handler)
+    {
+        _handler = handler;
+    }
+
+    public MessageList(
+        ThemeRegistry themes,
+        TokenResolver resolver,
+        FontManager fonts,
+        ChunkRenderer chunkRenderer
+    )
     {
         _themes = themes;
         _resolver = resolver;
         _fonts = fonts;
+        _chunkRenderer = chunkRenderer;
     }
 
     public void Draw(Tab tab)
@@ -40,10 +55,6 @@ internal sealed class MessageList
         // No own ImRaii.Child here — MainWindow already wraps the message
         // area in one. Nesting would give the window two stacked scrolls
         // and a runaway content-height computation.
-        var theme = _themes.Active;
-        var textAbgr = ColourUtil.RgbaToAbgr(theme.Colors.TextPrimary);
-        var mutedAbgr = ColourUtil.RgbaToAbgr(theme.Colors.TextMuted);
-
         using var messages = tab.Messages.GetReadOnly(3);
         var compact = Plugin.Config.UseCompactDensity;
 
@@ -53,15 +64,15 @@ internal sealed class MessageList
         var pinnedToBottom = ImGui.GetScrollY() >= ImGui.GetScrollMaxY() - 1f;
 
         if (compact)
-            DrawCompact(messages, textAbgr, mutedAbgr);
+            DrawCompact(messages);
         else
-            DrawCard(tab, messages, textAbgr, mutedAbgr);
+            DrawCard(tab, messages);
 
         if (pinnedToBottom)
             ImGui.SetScrollHereY(1f);
     }
 
-    private void DrawCompact(IReadOnlyList<Message> messages, uint textAbgr, uint mutedAbgr)
+    private void DrawCompact(IReadOnlyList<Message> messages)
     {
         unsafe
         {
@@ -72,7 +83,7 @@ internal sealed class MessageList
                 while (clipper.Step())
                 {
                     for (var i = clipper.DisplayStart; i < clipper.DisplayEnd; i++)
-                        DrawCompactRow(messages[i], textAbgr, mutedAbgr);
+                        DrawCompactRow(messages[i]);
                 }
                 clipper.End();
             }
@@ -83,18 +94,18 @@ internal sealed class MessageList
         }
     }
 
-    private void DrawCompactRow(Message message, uint textAbgr, uint mutedAbgr)
+    private void DrawCompactRow(Message message)
     {
         var timestamp = FormatTimestamp(message.Date);
         var sender = message.SenderSource.TextValue;
-        var content = message.ContentSource.TextValue;
+        ImGui.TextUnformatted(
-        var line = string.IsNullOrEmpty(sender)
+            string.IsNullOrEmpty(sender) ? timestamp : $"{timestamp}  {sender}: "
-            ? $"{timestamp}  {content}"
+        );
-            : $"{timestamp}  {sender}: {content}";
+        ImGui.SameLine();
-        ImGui.TextUnformatted(line);
+        _chunkRenderer.DrawChunks(message.Content, wrap: true, handler: _handler, lineWidth: 0f);
     }
 
-    private void DrawCard(Tab tab, IReadOnlyList<Message> messages, uint textAbgr, uint mutedAbgr)
+    private void DrawCard(Tab tab, IReadOnlyList<Message> messages)
     {
         var tabId = tab.Identifier;
         for (var i = 0; i < messages.Count; i++)
@@ -127,11 +138,8 @@ internal sealed class MessageList
     {
         var timestamp = FormatTimestamp(message.Date);
         var sender = message.SenderSource.TextValue;
-        var content = message.ContentSource.TextValue;
         ImGui.TextUnformatted(string.IsNullOrEmpty(sender) ? timestamp : $"{timestamp}  {sender}");
-        ImGui.PushTextWrapPos(0f);
+        _chunkRenderer.DrawChunks(message.Content, wrap: true, handler: _handler, lineWidth: 0f);
-        ImGui.TextUnformatted(content);
-        ImGui.PopTextWrapPos();
     }
 
     private static string FormatTimestamp(DateTimeOffset date)