feat(quickshell): idle chain, drifting wallpaper, and a few fixes

- Idle is handled in the shell instead of hypridle: the screen dims
  slowly at 4 minutes, locks at 5, powers down at 6, and suspends at 15
  on battery. Idle inhibitors hold every stage off; Super+Shift+I does
  the same by hand and puts a cup on the rail.
- The shell draws the wallpaper (backdrop/), so hyprpaper is gone. The
  picture is drawn a little larger than the screen and drifts with the
  workspace a beat after the windows, and dims a shade while windows are
  open. The path lives in quickshell/wallpaper.
- The lock screen and power menu say "Take your time." instead of the
  NieR slogan.
- hyprpaper is no longer launched twice, the media module keeps the
  player that played last instead of an empty browser tab, and grouped
  windows show thin untitled tabs with their place in the group (2/3)
  in the bar title.
- qt6ct uses Darkly; the package list gains adw-gtk-theme and darkly-bin.

hypr/lua/look.lua

@@ -74,6 +74,10 @@ hl.config({
         font_family = "FiraCode Nerd Font",
         background_color = c.base,
         focus_on_activate = true,
+        -- The shell powers displays down after idle (quickshell/services/Idle.qml)
+        -- and back up when idle ends; these wake them even if it is not running.
+        key_press_enables_dpms = true,
+        mouse_move_enables_dpms = true,
     },
 
     group = {
@@ -82,37 +86,29 @@ hl.config({
             border_inactive = c.overlay,
         },
 
-        -- Tabs are solid slabs of the hull, not titles painted over the
-        -- wallpaper. Hyprland paints a tab's fill and its indicator from the
-        -- same colour, so the current tab is told apart by being lifted a step
-        -- and by its title taking the light, not by an accent fill — a light
-        -- fill would swallow its own title.
+        -- Tabs are thin rounded lines, not titled slabs. The bar already
+        -- writes the focused title and its place in the group ("2/3", in
+        -- quickshell/bar/ActiveWindow.qml), so titles here only repeated it in
+        -- a second font. Hyprland paints a tab's indicator in the same colour
+        -- as its fill, so with no fill the current tab is simply the light one.
         groupbar = {
-            font_family = "Noto Sans",
-            font_size = 10,
-            font_weight_active = "medium",
-            font_weight_inactive = "normal",
+            render_titles = false,
+            gradients = false,
 
-            height = 22,
-            indicator_height = 1,
+            indicator_height = 3,
             indicator_gap = 0,
-            gradients = true,
-            rounding = 6,
-            gradient_rounding = 6,
-            round_only_edges = true,
-            gradient_round_only_edges = true,
+            rounding = 2,
+            round_only_edges = false,
             keep_upper_gap = false,
-            gaps_in = 2,
+            gaps_in = 4,
             gaps_out = 0,
 
             col = {
-                active = c.overlay,
-                inactive = c.surface,
+                active = c.accent,
+                inactive = c.overlay,
                 locked_active = c.alarm,
-                locked_inactive = c.surface,
+                locked_inactive = c.overlay,
             },
-            text_color = c.accent,
-            text_color_inactive = c.muted,
         },
     },