Function plan_site_assets 

pub fn plan_site_assets(
    pages_dir: &Path,
    static_dir: &Path,
) -> Result<Vec<(String, String, Vec<u8>)>, String>

A built site’s planned assets as (path, content type, bytes) — the REAL table largo build bakes into the binary, exposed so asset_cache_lock holds the shipped names and headers rather than a copy of the rule.