Function journal_data_migration 

pub fn journal_data_migration(
    tx: &Connection,
    tag: &str,
    content_checksum: &str,
    applied_at: i64,
) -> Result<(), BookkeepingError>

Record a pure-data migration inside the caller’s captured transaction. The marker is the final captured row in that migration, so a zero-user-effect file is still durable and replay identity survives restore.