logiguard fork v2: patched GPUI on verified 8c74db0 tree

Rebuilt from the exact zed-industries/zed @ 8c74db00c4053d6c0a9037863d7bd048658da4ca
tree (previous orphan was based on a stale/wrong fetch). Same 3-file patch:
  - 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)

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

crates/env_var/src/env_var.rs

@@ -0,0 +1,40 @@
+use gpui_shared_string::SharedString;
+
+#[derive(Clone)]
+pub struct EnvVar {
+    pub name: SharedString,
+    /// Value of the environment variable. Also `None` when set to an empty string.
+    pub value: Option<String>,
+}
+
+impl EnvVar {
+    pub fn new(name: SharedString) -> Self {
+        let value = std::env::var(name.as_str()).ok();
+        if value.as_ref().is_some_and(|v| v.is_empty()) {
+            Self { name, value: None }
+        } else {
+            Self { name, value }
+        }
+    }
+
+    pub fn or(self, other: EnvVar) -> EnvVar {
+        if self.value.is_some() { self } else { other }
+    }
+}
+
+/// Creates a `LazyLock<EnvVar>` expression for use in a `static` declaration.
+#[macro_export]
+macro_rules! env_var {
+    ($name:expr) => {
+        ::std::sync::LazyLock::new(|| $crate::EnvVar::new(($name).into()))
+    };
+}
+
+/// Generates a `LazyLock<bool>` expression for use in a `static` declaration. Checks if the
+/// environment variable exists and is non-empty.
+#[macro_export]
+macro_rules! bool_env_var {
+    ($name:expr) => {
+        ::std::sync::LazyLock::new(|| $crate::EnvVar::new(($name).into()).value.is_some())
+    };
+}