organize the Helper Functions

those who make the program. the helper functions. they deserve better Ahh

src/wf_api/artifact_refs.py

@@ -0,0 +1,13 @@
+from __future__ import annotations
+
+from wf_artifacts import WorkflowArtifact, WorkflowCapabilityRef
+
+
+def artifact_capability_id(artifact: WorkflowArtifact) -> str:
+    """Return the stable workflow capability name for a saved artifact."""
+    return str(
+        WorkflowCapabilityRef(
+            artifact_id=artifact.id,
+            version=artifact.version,
+        )
+    )