Function write_archive_with_ai_index 

pub fn write_archive_with_ai_index<W: Write + Seek>(
    store: &VersionStore,
    writer: W,
    compress: &str,
    timestamp_filter: Option<&str>,
    index_dir: Option<&Path>,
    include_vectors: bool,
) -> Result<FxarExportStats>

Convenience wrapper: reads .foxing_index/ files via prepare_ai_extension_sections, then writes the archive with write_archive_seekable_with_ai.