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/shell.rs

@@ -44,7 +44,7 @@ impl Gallery {
             }
         });
         let focus = cx.focus_handle();
-        window.focus(&focus);
+        window.focus(&focus, cx);
         Self {
             page,
             pass: 0,
@@ -71,10 +71,7 @@ impl Gallery {
 
     /// Viewport height and furthest scroll, in pixels.
     pub fn scroll_extent(&self) -> (Pixels, Pixels) {
-        (
-            self.scroll.bounds().size.height,
-            self.scroll.max_offset().height,
-        )
+        (self.scroll.bounds().size.height, self.scroll.max_offset().y)
     }
 
     /// Scrolls until `target` sits inside the page. True if it moved.
@@ -87,7 +84,7 @@ impl Gallery {
         } else {
             return false;
         };
-        let y = (-self.scroll.offset().y + shift).clamp(px(0.0), self.scroll.max_offset().height);
+        let y = (-self.scroll.offset().y + shift).clamp(px(0.0), self.scroll.max_offset().y);
         self.scroll_to(y, cx);
         true
     }