Verified on 2026-10-10 with throwaway branches (deleted afterwards):
workflow_call and uses run from the same repository, another repository of
the organisation and a repository of another organisation, so MIL-003 needs
no copied-template fallback. Not tested: a private provider, secrets passed
to a called workflow, and a tag reference. Review it (RC-033) and update
TM-001.
Task: MIL-003#1
