Function process_pending_spawn_mesh_asset 

pub fn process_pending_spawn_mesh_asset(
    project_vfs: Option<&Arc<Mutex<ProjectVfs>>>,
    world: &mut GameWorld,
    editor_state: &Arc<Mutex<EditorState>>,
)

Drains [EditorState::pending_spawn_mesh_asset]: spawns a MeshRef::Asset entity at the drop point. Set by dragging a mesh tile onto the viewport; the asset_resolver_system loads the mesh next tick.