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/vim/test_data/test_caret_mark.json

@@ -0,0 +1,35 @@
+{"Put":{"state":"Line one\nLine two\nLine three\nˇLine four\nLine five\n"}}
+{"Key":"c"}
+{"Key":"w"}
+{"Key":"shift-s"}
+{"Key":"t"}
+{"Key":"r"}
+{"Key":"a"}
+{"Key":"i"}
+{"Key":"g"}
+{"Key":"h"}
+{"Key":"t"}
+{"Key":"space"}
+{"Key":"t"}
+{"Key":"h"}
+{"Key":"i"}
+{"Key":"n"}
+{"Key":"g"}
+{"Key":"escape"}
+{"Key":"j"}
+{"Key":"j"}
+{"Key":"'"}
+{"Key":"^"}
+{"Get":{"state":"Line one\nLine two\nLine three\nˇStraight thing four\nLine five\n","mode":"Normal"}}
+{"Key":"`"}
+{"Key":"^"}
+{"Get":{"state":"Line one\nLine two\nLine three\nStraight thingˇ four\nLine five\n","mode":"Normal"}}
+{"Key":"k"}
+{"Key":"a"}
+{"Key":"!"}
+{"Key":"escape"}
+{"Key":"k"}
+{"Key":"g"}
+{"Key":"i"}
+{"Key":"?"}
+{"Get":{"state":"Line one\nLine two\nLine three!?ˇ\nStraight thing four\nLine five\n","mode":"Insert"}}