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/extension_api/build.rs

@@ -0,0 +1,15 @@
+fn main() {
+    let version = std::env::var("CARGO_PKG_VERSION").unwrap();
+    let out_dir = std::env::var("OUT_DIR").unwrap();
+
+    let mut parts = version.split(|c: char| !c.is_ascii_digit());
+    let major = parts.next().unwrap().parse::<u16>().unwrap().to_be_bytes();
+    let minor = parts.next().unwrap().parse::<u16>().unwrap().to_be_bytes();
+    let patch = parts.next().unwrap().parse::<u16>().unwrap().to_be_bytes();
+
+    std::fs::write(
+        std::path::Path::new(&out_dir).join("version_bytes"),
+        [major[0], major[1], minor[0], minor[1], patch[0], patch[1]],
+    )
+    .unwrap();
+}