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/markdown/examples/markdown_as_child.rs

@@ -0,0 +1,113 @@
+use assets::Assets;
+use gpui::{Entity, KeyBinding, Length, StyleRefinement, WindowOptions, rgb};
+use language::LanguageRegistry;
+use markdown::{Markdown, MarkdownElement, MarkdownStyle};
+use node_runtime::NodeRuntime;
+use settings::SettingsStore;
+use std::sync::Arc;
+use theme::LoadThemes;
+use ui::div;
+use ui::prelude::*;
+
+const MARKDOWN_EXAMPLE: &str = r#"
+this text should be selectable
+
+wow so cool
+
+## Heading 2
+"#;
+pub fn main() {
+    env_logger::init();
+
+    gpui_platform::application().with_assets(Assets).run(|cx| {
+        let store = SettingsStore::test(cx);
+        cx.set_global(store);
+        cx.bind_keys([KeyBinding::new("cmd-c", markdown::Copy, None)]);
+
+        let node_runtime = NodeRuntime::unavailable();
+        let language_registry = Arc::new(LanguageRegistry::new(cx.background_executor().clone()));
+        let fs = fs::FakeFs::new(cx.background_executor().clone());
+        languages::init(language_registry, fs, node_runtime, cx);
+        theme_settings::init(LoadThemes::JustBase, cx);
+        Assets.load_fonts(cx).unwrap();
+
+        cx.activate(true);
+        let _ = cx.open_window(WindowOptions::default(), |_, cx| {
+            cx.new(|cx| {
+                let markdown = cx.new(|cx| Markdown::new(MARKDOWN_EXAMPLE.into(), None, None, cx));
+
+                HelloWorld { markdown }
+            })
+        });
+    });
+}
+struct HelloWorld {
+    markdown: Entity<Markdown>,
+}
+
+impl Render for HelloWorld {
+    fn render(&mut self, _window: &mut Window, cx: &mut Context<Self>) -> impl IntoElement {
+        let markdown_style = MarkdownStyle {
+            base_text_style: gpui::TextStyle {
+                font_family: "Zed Mono".into(),
+                color: cx.theme().colors().text,
+                ..Default::default()
+            },
+            code_block: StyleRefinement {
+                text: gpui::TextStyleRefinement {
+                    font_family: Some("Zed Mono".into()),
+                    background_color: Some(cx.theme().colors().editor_background),
+                    ..Default::default()
+                },
+                margin: gpui::EdgesRefinement {
+                    top: Some(Length::Definite(rems(4.).into())),
+                    left: Some(Length::Definite(rems(4.).into())),
+                    right: Some(Length::Definite(rems(4.).into())),
+                    bottom: Some(Length::Definite(rems(4.).into())),
+                },
+                ..Default::default()
+            },
+            inline_code: gpui::TextStyleRefinement {
+                font_family: Some("Zed Mono".into()),
+                background_color: Some(cx.theme().colors().editor_background),
+                ..Default::default()
+            },
+            rule_color: Color::Muted.color(cx),
+            block_quote_border_color: Color::Muted.color(cx),
+            block_quote: gpui::TextStyleRefinement {
+                color: Some(Color::Muted.color(cx)),
+                ..Default::default()
+            },
+            link: gpui::TextStyleRefinement {
+                color: Some(Color::Accent.color(cx)),
+                underline: Some(gpui::UnderlineStyle {
+                    thickness: px(1.),
+                    color: Some(Color::Accent.color(cx)),
+                    wavy: false,
+                }),
+                ..Default::default()
+            },
+            syntax: cx.theme().syntax().clone(),
+            selection_background_color: cx.theme().colors().element_selection_background,
+            heading: Default::default(),
+            ..Default::default()
+        };
+
+        div()
+            .flex()
+            .bg(rgb(0x2e7d32))
+            .size(Length::Definite(px(700.0).into()))
+            .justify_center()
+            .items_center()
+            .shadow_lg()
+            .border_1()
+            .border_color(rgb(0x0000ff))
+            .text_xl()
+            .text_color(rgb(0xffffff))
+            .child(
+                div()
+                    .child(MarkdownElement::new(self.markdown.clone(), markdown_style))
+                    .p_20(),
+            )
+    }
+}