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/call/src/call_impl/participant.rs

@@ -0,0 +1,51 @@
+use client::{ParticipantIndex, User, proto};
+use collections::HashMap;
+use gpui::WeakEntity;
+use livekit_client::AudioStream;
+use project::Project;
+use std::sync::Arc;
+
+pub use livekit_client::TrackSid;
+pub use livekit_client::{RemoteAudioTrack, RemoteVideoTrack};
+
+#[derive(Clone, Default)]
+pub struct LocalParticipant {
+    pub projects: Vec<proto::ParticipantProject>,
+    pub active_project: Option<WeakEntity<Project>>,
+    pub role: proto::ChannelRole,
+}
+
+impl LocalParticipant {
+    pub fn can_write(&self) -> bool {
+        matches!(
+            self.role,
+            proto::ChannelRole::Admin | proto::ChannelRole::Member
+        )
+    }
+}
+
+pub struct RemoteParticipant {
+    pub user: Arc<User>,
+    pub peer_id: proto::PeerId,
+    pub role: proto::ChannelRole,
+    pub projects: Vec<proto::ParticipantProject>,
+    pub location: workspace::ParticipantLocation,
+    pub participant_index: ParticipantIndex,
+    pub muted: bool,
+    pub speaking: bool,
+    pub video_tracks: HashMap<TrackSid, RemoteVideoTrack>,
+    pub audio_tracks: HashMap<TrackSid, (RemoteAudioTrack, AudioStream)>,
+}
+
+impl RemoteParticipant {
+    pub fn has_video_tracks(&self) -> bool {
+        !self.video_tracks.is_empty()
+    }
+
+    pub fn can_write(&self) -> bool {
+        matches!(
+            self.role,
+            proto::ChannelRole::Admin | proto::ChannelRole::Member
+        )
+    }
+}