blank_issues_enabled: false only hides the chooser link — the CLI / API /
direct URLs still create template-less issues (e.g. #174 by a CONTRIBUTOR).
This workflow enforces the policy: an issue opened by someone without write
access that carries no template label (bug / enhancement) is commented on and
closed as not-planned. Proper bug reports / feature requests and write-access
users are unaffected.
Takes effect only once on the default branch (main).
