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/title_bar/Cargo.toml

@@ -0,0 +1,81 @@
+[package]
+name = "title_bar"
+version = "0.1.0"
+edition.workspace = true
+publish.workspace = true
+license = "GPL-3.0-or-later"
+
+[lints]
+workspace = true
+
+[lib]
+path = "src/title_bar.rs"
+doctest = false
+
+[features]
+default = []
+
+test-support = [
+    "call/test-support",
+    "client/test-support",
+
+    "gpui/test-support",
+
+    "project/test-support",
+    "remote/test-support",
+    "util/test-support",
+    "workspace/test-support",
+    "recent_projects/test-support",
+]
+
+[dependencies]
+agent_settings.workspace = true
+anyhow.workspace = true
+auto_update.workspace = true
+fs.workspace = true
+platform_title_bar.workspace = true
+call.workspace = true
+channel.workspace = true
+chrono.workspace = true
+client.workspace = true
+cloud_api_types.workspace = true
+db.workspace = true
+git_ui.workspace = true
+gpui = { workspace = true, features = ["screen-capture"] }
+icons.workspace = true
+livekit_client.workspace = true
+notifications.workspace = true
+project.workspace = true
+recent_projects.workspace = true
+remote.workspace = true
+remote_connection.workspace = true
+rpc.workspace = true
+semver.workspace = true
+schemars.workspace = true
+serde.workspace = true
+settings.workspace = true
+smallvec.workspace = true
+telemetry.workspace = true
+theme.workspace = true
+ui.workspace = true
+util.workspace = true
+workspace.workspace = true
+zed_actions.workspace = true
+arrayvec = "0.7.6"
+
+[target.'cfg(windows)'.dependencies]
+windows.workspace = true
+
+[dev-dependencies]
+call = { workspace = true, features = ["test-support"] }
+client = { workspace = true, features = ["test-support"] }
+gpui = { workspace = true, features = ["test-support"] }
+notifications = { workspace = true, features = ["test-support"] }
+project = { workspace = true, features = ["test-support"] }
+release_channel.workspace = true
+remote = { workspace = true, features = ["test-support"] }
+rpc = { workspace = true, features = ["test-support"] }
+semver.workspace = true
+settings = { workspace = true, features = ["test-support"] }
+util = { workspace = true, features = ["test-support"] }
+workspace = { workspace = true, features = ["test-support"] }