Function extract_dependencies 

pub(crate) fn extract_dependencies(
    stmt: &Statement,
    default_database: &str,
    default_schema: &str,
) -> (BTreeSet<ObjectId>, BTreeSet<Cluster>)

Extract all dependencies from a statement.

Returns a tuple of (object_dependencies, cluster_dependencies).

This function is public to allow the changeset module to analyze cluster dependencies for incremental deployment.