ui: wrap window content in GtkScrolledWindow

The Lan Mouse window previously couldn't scroll its preference
groups when the window height was reduced below the natural
content height — content was simply clipped, with no way to
reach the lower groups. AdwStatusPage doesn't include built-in
scrolling.

Wrap the AdwStatusPage in a GtkScrolledWindow inside the
existing AdwToastOverlay, with vertical scroll on demand and
horizontal scroll disabled (we use AdwClamp for horizontal
sizing). propagate-natural-height keeps the window's preferred
size identical when content fits, so existing layout behavior
on tall windows is unchanged.

Effect: when the user resizes the window shorter than the
natural content height (or has a small display), all preference
groups remain reachable via vertical scroll.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Author: jondkinney

lan-mouse-gtk/resources/window.ui

@@ -37,6 +37,7 @@
                 <property name="hexpand">true</property>
                 <property name="hscrollbar-policy">never</property>
                 <property name="vscrollbar-policy">automatic</property>
+                <property name="propagate-natural-height">true</property>
                 <child>
                   <object class="AdwStatusPage">
                     <property name="title" translatable="yes">Lan Mouse</property>