- WorkflowRegistry now mirrors StepRegistry: _load refuses symlinked
parents/registry file and normalizes a non-dict workflows field;
save() rejects symlinked paths before writing.
- workflow add --dev requires workflow.yml to be a regular file so a
directory named workflow.yml gets the documented CLI error instead of
an uncaught IsADirectoryError.
Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>