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/menu/Cargo.toml

@@ -0,0 +1,16 @@
+[package]
+name = "menu"
+version = "0.1.0"
+edition.workspace = true
+publish.workspace = true
+license = "GPL-3.0-or-later"
+
+[lints]
+workspace = true
+
+[lib]
+path = "src/menu.rs"
+doctest = false
+
+[dependencies]
+gpui.workspace = true

crates/menu/LICENSE-GPL

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

crates/menu/src/menu.rs

@@ -0,0 +1,37 @@
+use gpui::actions;
+
+// If the zed binary doesn't use anything in this crate, it will be optimized away
+// and the actions won't initialize. So we just provide an empty initialization function
+// to be called from main.
+//
+// These may provide relevant context:
+// https://github.com/rust-lang/rust/issues/47384
+// https://github.com/mmastrac/rust-ctor/issues/280
+pub fn init() {}
+
+actions!(
+    menu,
+    [
+        /// Cancels the current menu operation.
+        Cancel,
+        /// Confirms the selected menu item.
+        Confirm,
+        /// Performs secondary confirmation action.
+        SecondaryConfirm,
+        /// Selects the previous item in the menu.
+        SelectPrevious,
+        /// Selects the next item in the menu.
+        SelectNext,
+        /// Selects the first item in the menu.
+        SelectFirst,
+        /// Selects the last item in the menu.
+        SelectLast,
+        /// Enters a submenu (navigates to child menu).
+        SelectChild,
+        /// Exits a submenu (navigates to parent menu).
+        SelectParent,
+        /// Restarts the menu from the beginning.
+        Restart,
+        EndSlot,
+    ]
+);