Polymorphic env: block. Normally a map of name → value, but in some
real-world workflows the entire env: value is a template expression
(e.g. env: ${{ matrix }}), where the shape resolves at runtime.
Returns true if the workflow’s on: triggers include pull_request_target.
GHA on: is polymorphic: string, sequence, or mapping.
Returns true when a GHA if: expression matches the standard fork-check
pattern: github.event.pull_request.head.repo.fork == false (or the
negated != true), or the equivalent
github.event.pull_request.head.repo.full_name == github.repository.
Whitespace is normalised before matching so the canonical Grafana form
(if: github.event.pull_request.head.repo.full_name == github.repository)
is detected alongside the more terse repo.fork == false variant.