refactor(focus): drive focus through UiContext::focus_widget / unfocus_widget

A direct w.focus() / w.unfocus() left the window's record of focus (the Tab
walk, the accessibility tree) behind: on a widget that had let go, or beside
a newly focused one. The UiContext helpers do what the direct call did and
keep the record in step (cce-ui's global-state RFC, phase 2).

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

 src/main.rs | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/src/main.rs b/src/main.rs
index cfe853d..c189739 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -273,7 +273,7 @@ impl WeatherApp {
             if self.results_btns[i].take_click() {
                 if let Some(loc) = self.results.get(i).cloned() {
                     self.clear_search();
-                    self.search.unfocus();
+                    self.ui_context.unfocus_widget(&mut self.search);
                     self.set_location(loc);
                 }
             }
@@ -727,7 +727,7 @@ impl Application for WeatherApp {
                     // One match needs no question.
                     Ok(mut list) if list.len() == 1 => {
                         self.clear_search();
-                        self.search.unfocus();
+                        self.ui_context.unfocus_widget(&mut self.search);
                         self.set_location(list.remove(0));
                     }
                     Ok(list) => self.results = list,
@@ -902,7 +902,7 @@ impl Application for WeatherApp {
                 }
                 Key::Named(NamedKey::Escape) if self.picking() || self.search.editing => {
                     self.results.clear();
-                    self.search.unfocus();
+                    self.ui_context.unfocus_widget(&mut self.search);
                     self.needs_rebuild = true;
                     *needs_rebuild = true;
                     return None;