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/zed_env_vars/Cargo.toml

@@ -0,0 +1,18 @@
+[package]
+name = "zed_env_vars"
+version = "0.1.0"
+edition.workspace = true
+publish.workspace = true
+license = "GPL-3.0-or-later"
+
+[lints]
+workspace = true
+
+[lib]
+path = "src/zed_env_vars.rs"
+
+[features]
+default = []
+
+[dependencies]
+env_var.workspace = true

crates/zed_env_vars/LICENSE-GPL

@@ -0,0 +1 @@
+../../LICENSE-GPL

crates/zed_env_vars/src/zed_env_vars.rs

@@ -0,0 +1,6 @@
+pub use env_var::{EnvVar, bool_env_var, env_var};
+use std::sync::LazyLock;
+
+/// Whether Zed is running in stateless mode.
+/// When true, Zed will use in-memory databases instead of persistent storage.
+pub static ZED_STATELESS: LazyLock<bool> = bool_env_var!("ZED_STATELESS");