Function migrate_paths 

pub async fn migrate_paths(
    inputs: &[InputRule],
    output_root: &Path,
    options: &MigrateOptions,
) -> Result<MigrateSummary, Error>

Migrate discovered inputs and write results under output_root.

Uses atomic writes via crate::io::write_file_atomic. Skips outputs that already exist unless MigrateOptions::force is set.