fix: dark-theme hero buttons green in dark mode; correct source-order comment

Both ::deep and global selectors are (0,3,0); override wins on source order
(deepdrft-styles.css linked after scoped bundle in App.razor).

DeepDrftPublic.Client/Controls/WaveformVisualizerControlPopover.razor

@@ -29,15 +29,17 @@
    the shared WaveformVisualizerControlState and raises Changed; the visualizer bridge subscribes. This
    host only toggles open/closed and centers the panel — it stays purely presentational. *@
 
-<MudTooltip Text="Visualizer settings">
-    <MudIconButton Icon="@(_open ? DDIcons.LavaLampFilled : DDIcons.LavaLamp)"
-                   Size="@IconSize"
-                   Color="Color.Secondary"
-                   Disabled="@(!RendererInfo.IsInteractive)"
-                   OnClick="@Toggle"
-                   aria-label="Visualizer settings"
-                   aria-expanded="@_open" />
-</MudTooltip>
+<div class="dd-lava-lamp-trigger">
+    <MudTooltip Text="Visualizer settings">
+        <MudIconButton Icon="@(_open ? DDIcons.LavaLampFilled : DDIcons.LavaLamp)"
+                       Size="@IconSize"
+                       Color="Color.Secondary"
+                       Disabled="@(!RendererInfo.IsInteractive)"
+                       OnClick="@Toggle"
+                       aria-label="Visualizer settings"
+                       aria-expanded="@_open" />
+    </MudTooltip>
+</div>
 
 @* The tinted modal scrim that also HOLDS the panel. DarkBackground = the mild tint; OnClick on the scrim
    dismisses (knob-drag-safe, see header). The panel is the overlay's centered child; it stops click