fix(gtk): tray-menu arrows via USER-priority counter-rule; show menu icons

Two corrections to ac7e6bd, which broke the bar it meant to spare:

1. Scoping the waybar '*' reset to 'window#waybar *' gave every reset
   property id-level specificity, so it started BEATING the later
   class rules (Boreal's pill border-radius/borders, workspace pills)
   that plain '*' correctly lost to — visibly wrecking the bar.
   Reverted all three stylesheets to the plain '*' block (bar restored
   byte-identical to pre-ac7e6bd) and instead restored the arrow where
   priority genuinely outranks waybar's stylesheet: stylix's gtk.css
   loads at USER priority (800) vs waybar's APPLICATION (600), so a
   'menu menuitem arrow { min-width/height: 16px }' there survives the
   reset in Waybar-hosted menus — the exact mechanism the neighbouring
   check/radio rule already uses for the same collapse. NB comments at
   each '*' block warn against re-scoping.

2. The 'missing icons' were never just arrows: GTK3 ships
   gtk-menu-images=false since 3.10, so image menu items (nm-applet's
   Wi-Fi list, udiskie) render iconless everywhere. Set
   gtk.gtk3.extraConfig.gtk-menu-images = 1 (merges into the
   settings.ini Stylix already writes).

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

themes/executive-slate/waybar.css

@@ -21,11 +21,11 @@
 @define-color warn      #DBA85A;
 @define-color bad       #D06B71;
 
-/* Scoped to the bar window: Waybar's stylesheet applies process-wide, so a
-   bare `*` also hits the SNI tray menus Waybar hosts (nm-applet & co) —
-   `min-height: 0` there collapses the submenu arrow node to invisible. */
-window#waybar,
-window#waybar * {
+/* NB: this `*` reset reaches the SNI tray menus Waybar hosts too — the
+   menu-side damage (collapsed arrows) is undone by USER-priority rules in
+   stylix.nix. Do NOT scope it to window#waybar: the id's specificity would
+   beat the class rules below and wreck the bar. */
+* {
   /* Mono Nerd face first for status glyphs: proportional "Symbols Nerd
      Font" has tight right bearings that make icon+percentage collide. */
   font-family: "Symbols Nerd Font Mono", "Inter", "JetBrainsMono Nerd Font", sans-serif;
@@ -183,11 +183,6 @@ tooltip {
   background: @surface;
   border: 1px solid @overlay;
   border-radius: 4px;
-  /* Tooltips are separate toplevels, outside the window#waybar scope —
-     restate the bar font (calendar/calcurse columns need the mono face). */
-  font-family: "Symbols Nerd Font Mono", "Inter", "JetBrainsMono Nerd Font", sans-serif;
-  font-size: 13px;
-  font-weight: 500;
 }
 tooltip label {
   color: @text;