fix(ui): match retail spell bar controls

Place favorite-bar arrows by their authored sides, import rollover and pressed media through the shared scrollbar, and preserve manual offsets across passive refreshes. Carry the mixed-parent DAT anchor chain to a fixed 18-cell favorite viewport so overflow controls and the Cast button remain inside the retail-sized combat frame.

Co-authored-by: Codex <codex@openai.com>

src/AcDream.App/UI/RetailUiRuntime.cs

@@ -764,11 +764,12 @@ public sealed class RetailUiRuntime : IDisposable
                 strings.Resolve);
             labels = info is null ? null : CombatUiLabels.Resolve(info, strings);
         }
-        if (layout is null || labels is null)
+        if (info is null || layout is null || labels is null)
         {
             Console.WriteLine("[M2] combat: LayoutDesc 0x21000073 not found.");
             return;
         }
+        float combatWidth = RetailCombatLayout.FitFavoriteSlots(layout);
 
         CombatUiController? controller = Layout.CombatUiController.Bind(
             layout,
@@ -821,9 +822,13 @@ public sealed class RetailUiRuntime : IDisposable
             {
                 WindowName = WindowNames.Combat,
                 Chrome = RetailWindowChrome.Imported,
-                Left = Math.Max(0f, (Host.Root.Width - root.Width) * 0.5f),
+                Left = 0f,
                 Top = Math.Max(0f, Host.Root.Height - root.Height - 10f),
+                ContentWidth = combatWidth,
+                DatConstraintSource = info,
+                OuterAnchors = AnchorEdges.Left | AnchorEdges.Bottom,
                 Visible = false,
+                Draggable = false,
                 Resizable = false,
                 ResizeX = false,
                 ResizeY = false,