Function replace_item_bindings 

pub fn replace_item_bindings(
    element: &Element,
    item: &Value,
    index: usize,
) -> Element

Replace item bindings (Value::Binding with is_item() or TemplateString with item bindings) with actual item values OPTIMIZED: Uses single-pass replacement instead of O(n²) repeated scans This is a convenience wrapper that uses “item” as the default item name.