{% for key, value in tree.items() %}
{% if value is mapping %}
{{ key }}
{{ render_file_tree(value, level + 1) }}
{% else %}
{# --- Logic to check if file is previewable --- #}
{% set filename_lower = key|lower %}
{% set file_ext = filename_lower.split('.')[-1] if '.' in filename_lower else '' %}
{% set is_previewable = file_ext not in non_previewable_extensions %}
{% set checkbox_id = 'file_' ~ value|replace('/', '_')|replace('.', '_') %}
{# --- End logic --- #}