fix(ui): shrink wizard window and fold the Fox banner by default

Smoke feedback v1.5.2 R1: the 900x560 default size dominated the
screen and the centred MonoFont fox silhouette filled the welcome
step. Default size drops to 720x480, MinimumSize to 600x400, so
the wizard fits comfortably on a sub-monitor and still leaves the
power-settings step readable when shrunk. Step 1 wraps the banner
in a folded TreeNode (label "Hellion Forge", same anchor pattern
the v1.5.1 wizard used) so the onboarding copy stays the primary
focus and users opt into the silhouette explicitly.

HellionChat/Ui/FirstRunWizard.cs

@@ -38,10 +38,10 @@ public sealed class FirstRunWizard : Window
 
         Flags = ImGuiWindowFlags.NoCollapse | ImGuiWindowFlags.NoDocking;
         SizeCondition = ImGuiCond.Appearing;
-        Size = new Vector2(900, 560);
+        Size = new Vector2(720, 480);
         SizeConstraints = new WindowSizeConstraints
         {
-            MinimumSize = new Vector2(720, 480),
+            MinimumSize = new Vector2(600, 400),
             MaximumSize = new Vector2(float.MaxValue, float.MaxValue),
         };
     }
@@ -150,16 +150,25 @@ public sealed class FirstRunWizard : Window
         ImGui.TextUnformatted(HellionStrings.Wizard_Step1_Title);
         ImGui.Spacing();
 
+        // Banner is opt-in: the full silhouette dominates the wizard window
+        // at the default size, so the TreeNode is folded by default and the
+        // onboarding copy stays the primary focus. Mirrors the pre-rewrite
+        // collapsible anchor from v1.5.1.
+        using (var tree = ImRaii.TreeNode("Hellion Forge"))
+        {
+            if (tree.Success)
+            {
                 using (Plugin.Interface.UiBuilder.MonoFontHandle.Push())
                 {
-            // Centre the banner across the available region. Spec Z.96
-            // calls for a zentrierten Mono-Font-Block. CalcTextSize must
-            // run inside the MonoFont push so the measurement matches the
-            // glyph width actually used for rendering.
+                    // CalcTextSize must run inside the MonoFont push so the
+                    // measurement matches the glyph width actually used for
+                    // rendering.
                     var bannerSize = ImGui.CalcTextSize(HellionForgeAscii.FoxBanner);
                     ImGui.SetCursorPosX((ImGui.GetContentRegionAvail().X - bannerSize.X) * 0.5f);
                     ImGui.TextUnformatted(HellionForgeAscii.FoxBanner);
                 }
+            }
+        }
 
         ImGui.Spacing();
         ImGui.TextWrapped(HellionStrings.Wizard_Step1_Subtitle);