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.

src/navigation/steps.rs

@@ -193,7 +193,7 @@ impl RenderOnce for Steps {
                     .flex_1()
                     .items_center()
                     .gap_3()
-                    .when(ix + 1 == count, |step| step.flex_none())
+                    .when(ix + 1 == count, |step| step.flex_grow_0().flex_shrink_0())
                     .child(head.child(circle).child(words))
                     .children(after)
                     .into_any_element()
@@ -337,7 +337,7 @@ impl RenderOnce for Wizard {
                 wizard.child(
                     Steps::new((id.clone(), "steps"), self.steps, current).on_select(
                         move |to, window, cx| {
-                            window.focus(&jumped);
+                            window.focus(&jumped, cx);
                             jump(to, window, cx)
                         },
                     ),
@@ -355,7 +355,7 @@ impl RenderOnce for Wizard {
                             .disabled(current == 0)
                             .on_click(move |_, window, cx| {
                                 if current == 1 {
-                                    window.focus(&to_advance);
+                                    window.focus(&to_advance, cx);
                                 }
                                 back(current - 1, window, cx)
                             }),