chore: root_plate_* — cce-ui 7a-2 caller migration

Mechanical rename onto cce-ui's canonical root-plate getters
(cce-ui@c8e0ab3, RFC Phase 7a); behavior unchanged, same config slots.

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

diff --git a/src/main.rs b/src/main.rs
index 2f1d408..e42d5d1 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -429,7 +429,7 @@ impl Application for TextEditorApp {
         let w = self.width as f32;
         let h = self.height as f32;
         let status_y = h - 30.0;
-        let radius = cce_ui::colors::backplate_corner_radius();
+        let radius = cce_ui::colors::root_plate_corner_radius();
         if radius > 0.1 {
             pc.rounded_rect(Rect { x: 0.0, y: 0.0, width: w, height: h }, radius, (true, true, true, true), [0.05, 0.05, 0.07, 1.0]);
             pc.rounded_rect(Rect { x: 0.0, y: 0.0, width: w, height: 42.0 }, radius, (true, true, false, false), [0.08, 0.08, 0.12, 1.0]);