logiguard fork: GPUI xdg-activation keyboard-focus serial fix

Single-commit orphan branch: full zed-industries/zed @ 8c74db0 source tree
with a 3-file patch applied (no upstream history).

Patch (crates/gpui_linux/src/linux/wayland/):
  - serial.rs: add SerialKind::KeyboardEnter
  - client.rs: store wl_keyboard.enter serial; add latest_serial_of()
  - window.rs: activate() uses keyboard-enter serial (Mutter focus gate)

Mutter honors window activation only when the token carries the keyboard-
focus serial from wl_keyboard.enter; GPUI used a stale mouse-press serial.
See docs/tray-window-focus-wayland.md in logiguard.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

crates/gpui/examples/text_layout.rs

@@ -0,0 +1,111 @@
+#![cfg_attr(target_family = "wasm", no_main)]
+
+use gpui::{
+    App, Bounds, Context, FontStyle, FontWeight, StyledText, Window, WindowBounds, WindowOptions,
+    div, prelude::*, px, size,
+};
+use gpui_platform::application;
+
+struct HelloWorld {}
+
+impl Render for HelloWorld {
+    fn render(&mut self, _window: &mut Window, _cx: &mut Context<Self>) -> impl IntoElement {
+        div()
+            .bg(gpui::white())
+            .flex()
+            .flex_col()
+            .gap_2()
+            .p_4()
+            .size_full()
+            .child(div().child("Text left"))
+            .child(div().text_center().child("Text center"))
+            .child(div().text_right().child("Text right"))
+            .child(div().text_decoration_1().child("Text left (underline)"))
+            .child(
+                div()
+                    .text_center()
+                    .text_decoration_1()
+                    .child("Text center (underline)"),
+            )
+            .child(
+                div()
+                    .text_right()
+                    .text_decoration_1()
+                    .child("Text right (underline)"),
+            )
+            .child(div().line_through().child("Text left (line_through)"))
+            .child(
+                div()
+                    .text_center()
+                    .line_through()
+                    .child("Text center (line_through)"),
+            )
+            .child(
+                div()
+                    .text_right()
+                    .line_through()
+                    .child("Text right (line_through)"),
+            )
+            .child(
+                div()
+                    .flex()
+                    .gap_2()
+                    .justify_between()
+                    .child(
+                        div()
+                            .w(px(400.))
+                            .border_1()
+                            .border_color(gpui::blue())
+                            .p_1()
+                            .whitespace_nowrap()
+                            .overflow_hidden()
+                            .text_center()
+                            .child("A long non-wrapping text align center"),
+                    )
+                    .child(
+                        div()
+                            .w_32()
+                            .border_1()
+                            .border_color(gpui::blue())
+                            .p_1()
+                            .whitespace_nowrap()
+                            .overflow_hidden()
+                            .text_right()
+                            .child("100%"),
+                    ),
+            )
+            .child(div().flex().gap_2().justify_between().child(
+                StyledText::new("ABCD").with_highlights([
+                    (0..1, FontWeight::EXTRA_BOLD.into()),
+                    (2..3, FontStyle::Italic.into()),
+                ]),
+            ))
+    }
+}
+
+fn run_example() {
+    application().run(|cx: &mut App| {
+        let bounds = Bounds::centered(None, size(px(800.0), px(600.0)), cx);
+        cx.open_window(
+            WindowOptions {
+                window_bounds: Some(WindowBounds::Windowed(bounds)),
+                ..Default::default()
+            },
+            |_, cx| cx.new(|_| HelloWorld {}),
+        )
+        .unwrap();
+        cx.activate(true);
+    });
+}
+
+#[cfg(not(target_family = "wasm"))]
+fn main() {
+    run_example();
+}
+
+#[cfg(target_family = "wasm")]
+#[wasm_bindgen::prelude::wasm_bindgen(start)]
+pub fn start() {
+    gpui_platform::web_init();
+    run_example();
+}