feat(astal-menu): bouncy slide-in on open, springy pop on quad expand

- Main open: enable Hyprland's `layers` animation with the bouncy myBezier curve and
  a slide style, so the layer-shell control centre slides in from the top edge with a
  little overshoot instead of just appearing. (Also gives notifications/bar the same
  springy slide, which suits the DE.) A per-namespace layerrule was tried first but
  this hyprlua build doesn't honour its animation timing.
- Quad expand: a CSS @keyframes scale-bounce (scale 0.82 -> 1.05 -> 1.0) added to the
  expanded card on expand and cleared on collapse so it replays every time. Verified
  GTK4 CSS transforms/keyframes render on this build, and that the card scales during
  the animation.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01XUWCXM4KhjRkwheaA3X7bP

desktopenvs/hyprlua/astal-menu/style/style.css

@@ -42,6 +42,15 @@ drawingarea {
   opacity: 0.15;
 }
 
+/* bouncy pop when a quad expands (added in ui/quadgrid.py on expand) */
+@keyframes quad-pop {
+  0%   { transform: scale(0.82); opacity: 0.4; }
+  55%  { transform: scale(1.05); opacity: 1; }
+  78%  { transform: scale(0.985); }
+  100% { transform: scale(1.0); }
+}
+.quad-pop { animation: quad-pop 300ms ease-out; }
+
 .quad-card { min-height: 100px; }
 .section-title { color: @text; font-weight: bold; opacity: 0.85; }
 

desktopenvs/hyprlua/astal-menu/ui/quadgrid.py

@@ -52,7 +52,8 @@ class QuadGrid(Gtk.Overlay):
         self._expand_reveal.set_valign(Gtk.Align.FILL)
         self._expand_holder = Gtk.Box(orientation=Gtk.Orientation.VERTICAL)
         self._expand_holder.add_css_class("quad-expanded")
-        self._expand_reveal.set_child(bordered(self._expand_holder, radius=16, fill_bg=True))
+        self._expand_card = bordered(self._expand_holder, radius=16, fill_bg=True)
+        self._expand_reveal.set_child(self._expand_card)
         self.add_overlay(self._expand_reveal)
         # The overlay's holder is opaque; keep the whole overlay hidden unless a quad
         # is actually expanded, otherwise it paints over the 2x2 grid.
@@ -82,12 +83,16 @@ class QuadGrid(Gtk.Overlay):
             self._expand_holder.append(content)
         self._expanded_id = module_id
         self._expand_reveal.set_reveal_child(True)
+        # bouncy scale pop (CSS @keyframes); the class was cleared on collapse so
+        # re-adding it here replays the animation on every expand.
+        self._expand_card.add_css_class("quad-pop")
         self.grid.add_css_class("dimmed")
         card.on_show()
 
     def request_collapse(self) -> None:
         self._expand_reveal.set_reveal_child(False)
         self._expand_reveal.set_visible(False)
+        self._expand_card.remove_css_class("quad-pop")  # reset so the pop replays
         self._expanded_id = None
         self.grid.remove_css_class("dimmed")
         # Drop the reference to the reparented widget so the card can reuse it.

desktopenvs/hyprlua/hypr/hyprland.lua

@@ -207,6 +207,13 @@ hl.animation({ leaf = "fade",             enabled = true, speed = 7,  bezier = "
 -- from regular workspace transitions which use horizontal slides by default.
 hl.animation({ leaf = "specialWorkspace", enabled = true, speed = 10, bezier = "default",  style = "slidevert" })
 
+-- Layer-shell surfaces (the astal-menu control centre, notifications, the bar) slide
+-- in from their anchored edge with the bouncy myBezier curve, so opening the menu
+-- reads as a springy slide-down rather than a plain fade. (A per-namespace layerrule
+-- was tried but this hyprlua build doesn't honour its animation timing; the global
+-- `layers` leaf does.)
+hl.animation({ leaf = "layers",           enabled = true, speed = 5,  bezier = "myBezier", style = "slide" })
+
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