Function plan_dependencies 

pub fn plan_dependencies(
    operations: &[OperationEnvelope],
) -> Result<DependencyPlan, DependencyError>

Builds a stable O(V + E) dependency plan for operations contained in one batch. Dependencies outside the batch remain server-ledger prerequisites and are not graph edges.

Errors

Returns DependencyError::Duplicate for duplicate operation IDs and DependencyError::Cycle when no topological execution order exists.