refactor: corner reads via Element::corner_style (cce-ui 6bd batch 2)

corner_radius/rounded_corners left the Element trait; the aggregate loops
read both through the single corner_style() pair now. Behavior-preserving.

Co-Authored-By: Claude Fable 5 <[email protected]>
Claude-Session: https://claude.ai/code/session_018u7qTwzX95dd5ysAkaSCLk

 src/ti_widgets.rs | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/src/ti_widgets.rs b/src/ti_widgets.rs
index 55bf32d..130c2a9 100644
--- a/src/ti_widgets.rs
+++ b/src/ti_widgets.rs
@@ -108,10 +108,11 @@ impl ControlPanel {
                         let visible_bottom = cy_bottom.min(y_end);
                         let visible_h = visible_bottom - visible_top;
                         if visible_h > 0.0 {
+                            let (child_r, child_corners) = child.corner_style();
                             let radii_adjusted = if visible_top > cy_top || visible_bottom < cy_bottom {
                                 0.0
                             } else {
-                                child.corner_radius()
+                                child_r
                             };
                             quads.push((
                                 cx,
@@ -120,7 +121,7 @@ impl ControlPanel {
                                 visible_h,
                                 radii_adjusted,
                                 b_color,
-                                child.rounded_corners(),
+                                child_corners,
                             ));
                         }
                     }
@@ -185,7 +186,7 @@ impl ControlPanel {
             for child_ptr in &self.children {
                 let child = &**child_ptr;
                 let (cx, cy, cw, ch) = child.rect();
-                let has_rounded = child.rounded_corners() != (false, false, false, false);
+                let has_rounded = child.corner_style().1 != (false, false, false, false);
                 let has_bg = child.color()[3].abs() > 0.001;
 
                 for (qx, qy, qw, qh, qc) in child.all_quads(&ctx_dummy) {