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/src/db/tables/room_participant.rs

@@ -0,0 +1,62 @@
+use crate::db::{ChannelRole, ProjectId, RoomId, RoomParticipantId, ServerId, UserId};
+use rpc::ConnectionId;
+use sea_orm::entity::prelude::*;
+
+#[derive(Clone, Debug, PartialEq, Eq, DeriveEntityModel)]
+#[sea_orm(table_name = "room_participants")]
+pub struct Model {
+    #[sea_orm(primary_key)]
+    pub id: RoomParticipantId,
+    pub room_id: RoomId,
+    pub user_id: UserId,
+    pub answering_connection_id: Option<i32>,
+    pub answering_connection_server_id: Option<ServerId>,
+    pub answering_connection_lost: bool,
+    pub location_kind: Option<i32>,
+    pub location_project_id: Option<ProjectId>,
+    pub initial_project_id: Option<ProjectId>,
+    pub calling_user_id: UserId,
+    pub calling_connection_id: i32,
+    pub calling_connection_server_id: Option<ServerId>,
+    pub participant_index: Option<i32>,
+    pub role: Option<ChannelRole>,
+}
+
+impl Model {
+    pub fn answering_connection(&self) -> Option<ConnectionId> {
+        Some(ConnectionId {
+            owner_id: self.answering_connection_server_id?.0 as u32,
+            id: self.answering_connection_id? as u32,
+        })
+    }
+}
+
+#[derive(Copy, Clone, Debug, EnumIter, DeriveRelation)]
+pub enum Relation {
+    #[sea_orm(
+        belongs_to = "super::user::Entity",
+        from = "Column::UserId",
+        to = "super::user::Column::Id"
+    )]
+    User,
+    #[sea_orm(
+        belongs_to = "super::room::Entity",
+        from = "Column::RoomId",
+        to = "super::room::Column::Id"
+    )]
+    Room,
+}
+
+impl Related<super::user::Entity> for Entity {
+    fn to() -> RelationDef {
+        Relation::User.def()
+    }
+}
+
+impl Related<super::room::Entity> for Entity {
+    fn to() -> RelationDef {
+        Relation::Room.def()
+    }
+}
+
+impl ActiveModelBehavior for ActiveModel {}