pipeio_dag — query rule dependency graph

Goal

(promoted from note)

Context

(see source note)

Prompt

Implement pipeio_dag(pipe, flow, target=None) — static Snakefile analysis to extract rule dependency graph (nodes, edges, roots, leaves, path queries). No Snakemake DAG loading needed.

Reference capture: 20260325-211444-d420c1.

Acceptance Criteria

• [ ]

Result

(pending)