Vault-relative path (articles/<stem>.md or Reference/<stem>.md) for an
existing article/reference doc — the safe argv piece for git plumbing
(articleHistory/articleDiff), resolved via the same name normalization/
existence check as readArticle so a caller can't smuggle a path-traversal
or shell-metacharacter name through. Throws if the doc doesn't exist.
Vault-relative path (
articles/<stem>.mdorReference/<stem>.md) for an existing article/reference doc — the safe argv piece for git plumbing (articleHistory/articleDiff), resolved via the same name normalization/ existence check as readArticle so a caller can't smuggle a path-traversal or shell-metacharacter name through. Throws if the doc doesn't exist.