Function process_pending_assign_texture 

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

Drains [EditorState::pending_assign_texture]: assigns a dropped texture or .kmat to a specific entity. A .kmat becomes a MaterialRef::Asset; an image becomes the base_color_texture of a fresh inline standard material.