Function spawn_budgeted 

fn spawn_budgeted(
    world: &mut World,
    entity_assets: &mut HashMap<Entity, RenderableAsset>,
    remaining: &mut VecDeque<EntityRecord>,
    renderer: &Renderer<'_>,
    project_root: &Path,
) -> bool

Spawns up to LOAD_BUDGET_PER_FRAME worth of remaining entities into world/ entity_assets, returning true once remaining is empty (the load is finished) — shared by the “New/Open Project” and “open an additional scene as a new tab” load paths.