refactor: read popovers through get_widget

cce-ui's registry owns its widgets (owning registry, phase 5); its raw-pointer tree accessors are crate-private.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

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

diff --git a/src/main.rs b/src/main.rs
index 71c3bae..e5b4b02 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -2252,8 +2252,7 @@ impl Application for DataEditorApp {
         // them from the dl-text occlusion clamp (the is-overlay-text convention).
         {
             for &pop_id in &self.ui_context.active_popovers {
-                let Some(pop_ptr) = self.ui_context.tree.get_ptr(pop_id) else { continue };
-                let popover = unsafe { &*pop_ptr };
+                let Some(popover) = self.ui_context.get_widget(pop_id) else { continue };
                 if popover.popover_rect().is_none() {
                     continue;
                 }