Spacing: the window-edge inset is the roll plus the padding

The inset from the window edge read root_plate_padding(), a run of flat
face that on a rolled root plate begins only where the roll ends; it is
now layout::root_plate_inset(), the ladder's one number for that edge
(bevel_width plus the padding), so the flat run at the rim matches the
gap between siblings on the plate.

Co-Authored-By: Claude Fable 5.1 <[email protected]>

 src/main.rs | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/src/main.rs b/src/main.rs
index 44a31bb..2d9acda 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -765,7 +765,8 @@ impl Application for TerminalApp {
         _qh: &QueueHandle<EngineState<Self>>,
         sender: calloop::channel::Sender<Self::Message>,
     ) -> Self {
-        let pad = cce_ui::layout::root_plate_padding();
+        // The window-edge inset: the root plate's roll plus one padding.
+        let pad = cce_ui::layout::root_plate_inset();
         // `.3` is the `fonts { terminal }` family (this was the 7-tuple's
         // fontconfig `terminal` alias before the DE's fonts moved into the
         // shared KDL config), falling back to Noto Sans Mono.