resetInstance
Static helper that clears the process-wide SkillRegistry singleton. The next
call to getInstance() constructs a fresh registry with
no registered skills, cleared search paths, and no locked names.
Intended for use in test suites that need a clean registry per test case. Calling this in production is almost always a bug — every previously registered skill is forgotten, and any code still holding the old instance reference will diverge from the new one.
Returns
void