shape-doctor.py: a validator row prints the PYTHONPATH it ran the standard's TEMPLATE copy under, in sh's or PowerShell's dialect, and runs the root's OWN copy under none, so the manifest, pins and family rows' NEXT, pasted anywhere, prints the validator's own finding and exits with detail.exit instead of dying on ModuleNotFoundError: No module named 'repo_shape', and a root that lost its own repo_shape.py is no longer told its gate passes (#238) - #287