cpu_worker: add worker-thread framework

src/state.rs

@@ -13,6 +13,7 @@ use {
         clientmem::ClientMemOffset,
         compositor::LIBEI_SOCKET,
         config::ConfigProxy,
+        cpu_worker::CpuWorker,
         cursor::{Cursor, ServerCursors},
         cursor_user::{CursorUserGroup, CursorUserGroupId, CursorUserGroupIds, CursorUserIds},
         damage::DamageVisualizer,
@@ -214,6 +215,8 @@ pub struct State {
     pub enable_ei_acceptor: Cell<bool>,
     pub ei_clients: EiClients,
     pub slow_ei_clients: AsyncQueue<Rc<EiClient>>,
+    #[expect(dead_code)]
+    pub cpu_worker: Rc<CpuWorker>,
 }
 
 // impl Drop for State {