Function ensure_embedded_ddl_batch 

pub fn ensure_embedded_ddl_batch(sql: &str) -> Result<(), ReplicaError>

Preflight one trusted embedded schema batch before it touches SQLite. exec_ddl historically accepts multiple DDL statements and bounded ANALYZE, but it must not double as an unobserved DML escape hatch. Classification happens for the complete batch before the transaction begins, so a late INSERT cannot leave an earlier CREATE committed.