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 cc975a4..d5e9b85 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -288,7 +288,7 @@ impl cce_ui::engine::Application for SystemInterface {
         {
             let mut plate = cce_ui::color::to_linear([0x0a as f32 / 255.0, 0x1a as f32 / 255.0, 0x0e as f32 / 255.0, 1.0]);
             if plate[3] > 0.001 {
-                plate[3] = cce_ui::color::active_backplate_opacity();
+                plate[3] = cce_ui::color::root_plate_opacity();
             }
             let r = 12.0f32;
             pc.plate(Rect { x: 0.0, y: 0.0, width, height }, (r, r, r, r), plate, cce_ui::layout::bevel_width());