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/collab/tests/integration/collab_tests.rs

@@ -0,0 +1,54 @@
+use call::Room;
+use client::ChannelId;
+use gpui::{Entity, TestAppContext};
+
+mod agent_sharing_tests;
+mod auto_watch_tests;
+mod channel_buffer_tests;
+mod channel_guest_tests;
+mod channel_tests;
+mod collab_panel_tests;
+mod db_tests;
+mod editor_tests;
+mod following_tests;
+mod git_tests;
+mod integration_tests;
+mod notification_tests;
+mod random_channel_buffer_tests;
+mod random_project_collaboration_tests;
+mod randomized_test_helpers;
+mod remote_editing_collaboration_tests;
+mod test_server;
+
+pub use randomized_test_helpers::{
+    RandomizedTest, TestError, UserTestPlan, run_randomized_test, save_randomized_test_plan,
+};
+pub use test_server::{TestClient, TestServer};
+
+#[derive(Debug, Eq, PartialEq)]
+struct RoomParticipants {
+    remote: Vec<String>,
+    pending: Vec<String>,
+}
+
+fn room_participants(room: &Entity<Room>, cx: &mut TestAppContext) -> RoomParticipants {
+    room.read_with(cx, |room, _| {
+        let mut remote = room
+            .remote_participants()
+            .values()
+            .map(|participant| participant.user.github_login.clone().to_string())
+            .collect::<Vec<_>>();
+        let mut pending = room
+            .pending_participants()
+            .iter()
+            .map(|user| user.github_login.clone().to_string())
+            .collect::<Vec<_>>();
+        remote.sort();
+        pending.sort();
+        RoomParticipants { remote, pending }
+    })
+}
+
+fn channel_id(room: &Entity<Room>, cx: &mut TestAppContext) -> Option<ChannelId> {
+    cx.read(|cx| room.read(cx).channel_id())
+}