conventionalTypeFor function
The conventional-commit TYPE a bead's issueType derives — the FALLBACK
title's type ONLY (the inference picks its own type from the DIFF, which is
the whole point of the directive). IssueType is an OPEN set (an extension
type over the wire string), so an unknown type falls back to chore rather
than throwing.
Implementation
String conventionalTypeFor(IssueType issueType) => switch (issueType.wire) {
'feature' || 'epic' || 'story' => 'feat',
'bug' => 'fix',
_ => 'chore',
};