feat(servo-shell): add weft-shell-protocol client-side binding

Generate client-side protocol types from weft-shell-unstable-v1.xml
using wayland-scanner, following the same module structure as the
compositor server side.

- crates/weft-servo-shell/src/protocols/mod.rs: generate_interfaces!
  inside __interfaces submodule, generate_client_code! at client module
  level, with use wayland_client in scope. Re-exports
  ZweftShellManagerV1 and ZweftShellWindowV1 for use by embed_servo
  once the Wayland connection is established.

- New deps: wayland-client, wayland-backend, wayland-scanner, bitflags
  (version-matched to existing workspace resolution).

The binding compiles but is not yet wired into embed_servo(); that
connection is deferred until the Servo embedder contract is ready.

Cargo.lock

@@ -2274,8 +2274,12 @@ name = "weft-servo-shell"
 version = "0.1.0"
 dependencies = [
  "anyhow",
+ "bitflags 2.11.0",
  "tracing",
  "tracing-subscriber",
+ "wayland-backend",
+ "wayland-client",
+ "wayland-scanner",
 ]
 
 [[package]]

crates/weft-servo-shell/Cargo.toml

@@ -12,3 +12,7 @@ path = "src/main.rs"
 anyhow = "1.0"
 tracing = "0.1"
 tracing-subscriber = { version = "0.3", features = ["env-filter"] }
+wayland-client = "0.31"
+wayland-backend = "0.3"
+wayland-scanner = "0.31"
+bitflags = "2"

crates/weft-servo-shell/src/main.rs

@@ -2,6 +2,8 @@ use std::path::PathBuf;
 
 use anyhow::Context;
 
+mod protocols;
+
 fn main() -> anyhow::Result<()> {
     tracing_subscriber::fmt()
         .with_env_filter(

crates/weft-servo-shell/src/protocols/mod.rs

@@ -0,0 +1,20 @@
+#[allow(dead_code, non_camel_case_types, unused_unsafe, unused_variables)]
+#[allow(non_upper_case_globals, non_snake_case, unused_imports)]
+#[allow(missing_docs, clippy::all)]
+pub mod client {
+    use wayland_client;
+    use wayland_client::protocol::*;
+
+    pub mod __interfaces {
+        use wayland_client::protocol::__interfaces::*;
+        wayland_scanner::generate_interfaces!("../../protocol/weft-shell-unstable-v1.xml");
+    }
+    use self::__interfaces::*;
+
+    wayland_scanner::generate_client_code!("../../protocol/weft-shell-unstable-v1.xml");
+}
+
+#[allow(unused_imports)]
+pub use client::zweft_shell_manager_v1::ZweftShellManagerV1;
+#[allow(unused_imports)]
+pub use client::zweft_shell_window_v1::ZweftShellWindowV1;