docs: the viewport lip and the pane plates share one roll width

cce-ui's `plate_bevel_width` now returns `style.surface.relief.width`
(one roll width, 9310999a), so the comment contrasting the lip's width
with the interior panes' no longer describes two numbers.

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>

 src/render.rs | 10 ++++++----
 1 file changed, 6 insertions(+), 4 deletions(-)

diff --git a/src/render.rs b/src/render.rs
index 3dcb1e9..3a28a0e 100644
--- a/src/render.rs
+++ b/src/render.rs
@@ -359,10 +359,12 @@ impl State {
                     let vp_rect = rect(px, py, pw, ph);
                     let radii = self.pane_plate_radii(px, py, pw, ph);
                     if cce_ui::layout::control_relief() {
-                        // Window-edge roll width, NOT plate_bevel_width: the lip
-                        // matches the root plates of other windows
-                        // (style.surface.relief width), not the designer's
-                        // interior pane plates.
+                        // The window-edge roll width (style.surface.relief
+                        // width), read directly as the root plates of other
+                        // windows read it. The interior pane plates roll over
+                        // the same number through `plate_bevel_width` (one
+                        // roll width since 2026-09-28) unless a config still
+                        // carries the legacy `plate.bevel_width` override.
                         let depth = cce_ui::layout::bevel_width();
                         pc.plate_spec(&cce_ui::scene::paint::PlateSpec {
                             rect: vp_rect,