Port · Build: Zed's gpui at 1a28cff

gpui and gpui_platform now come from Zed's repo by git at 1a28cff,
the code gpui-pre 0.3.7 republishes, so the gallery can later build
for the browser. gpui takes stacker, as 0.2.2 always did, and
gpui_platform takes font-kit, without which macOS draws no text;
runtime_shaders moves to gpui_platform.

The API moved: focus, blur and Tab steps take cx, Corner is Anchor,
shaped lines paint with an alignment, defer_draw takes a content
mask, the inspector registers a factory, async updates return their
value, and wrapped lines are shared, not cloned. Updates through a
window context go through the window, so a closed window still ends
them as it did.

Where the new gpui behaves differently, Ely keeps its old intent.
Holds and reveals under a resting pointer survive typing through
gpui's input-modality-independent hover; previews the keyboard also
moves keep the default, and the calendar's leave ignores a key press.
Enter reaches a button inside the code editor, since gpui now arms a
key click on the press. The event logger skips a lone modifier. A
video and an image grid keep their shape in a flex column under
taffy 0.13, as a picture does.

AGENTS.md records the new stack and the rules this port changes; the
rest of the old gpui and taffy rules are re-tested in T44c.

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

examples/gallery/pages/chat/talk.rs

@@ -199,7 +199,7 @@ pub fn streaming(window: &mut Window, cx: &mut App) -> impl IntoElement + use<>
                                 cx.background_executor().timer(Duration::from_millis(600)).await;
                                 loop {
                                     cx.background_executor().timer(Duration::from_millis(45)).await;
-                                    let more = feeder.update(cx, |stream, cx| {
+                                    let more = cx.update(|_, cx| feeder.update(cx, |stream, cx| {
                                         let next = (stream.arrived + 7).min(ANSWER.len());
                                         stream.arrived = (next..=ANSWER.len())
                                             .find(|at| ANSWER.is_char_boundary(*at))
@@ -207,8 +207,8 @@ pub fn streaming(window: &mut Window, cx: &mut App) -> impl IntoElement + use<>
                                         stream.live = stream.arrived < ANSWER.len();
                                         cx.notify();
                                         stream.live
-                                    });
-                                    if !matches!(more, Ok(true)) {
+                                    }));
+                                    if !matches!(more.and_then(|inner| inner), Ok(true)) {
                                         break;
                                     }
                                 }