wayland: add jay_workspace_watcher

src/compositor.rs

@@ -196,6 +196,7 @@ fn start_compositor2(
         hardware_tick_cursor: Default::default(),
         testers: Default::default(),
         render_ctx_watchers: Default::default(),
+        workspace_watchers: Default::default(),
     });
     state.tracker.register(ClientId::from_raw(0));
     create_dummy_output(&state);