feat(quickshell): "Take your time." glows and flickers

A new GlowText component lights a line from inside: a soft two-layer
halo that breathes slowly, and every 4-14 seconds a short, uneven
stutter like a tube catching. Only opacity and the halo move, so the
glyphs stay on the pixel grid. The lock screen and the power menu use
it; the power menu's stops while it is closed.

quickshell/README.md

@@ -252,7 +252,8 @@ session.
 
 It is the wallpaper, barely softened, with the face set in the dark of the
 porthole: the mark, the time in light display type, the date, "Take your
-time.", a status log
+time." glowing faintly with the odd flicker (`components/GlowText.qml`), a
+status log
 (battery, network, what is playing, unread notices), and a rounded field that
 fills with dots as you type. The dots breathe while PAM checks; a wrong
 password turns them and the field's rim to rust and nudges the field once.