targetSkillName function
The skill name inside a builtin://skills/<name>/SKILL.md URI, or null.
Implementation
String? targetSkillName(String? target) {
if (target == null || !target.startsWith(builtinSkillPathPrefix)) {
return null;
}
final rest = target.substring(builtinSkillPathPrefix.length);
final slash = rest.indexOf('/');
if (slash <= 0 || rest.substring(slash) != '/SKILL.md') return null;
return rest.substring(0, slash);
}