ui: kill most users of parentui name and arg, replace with .copy()
#!/bin/shrm -rf ahg init acd atouch ahg ci -Am0hg mv a a1hg ci -m1hg co 0hg mv a a2hg uphg ci -m2touch ahg ci -Am3hg mv a bhg ci -Am4 ahg ci --debug --traceback -Am5 bhg verifyhg export --git tip