Installs panddas into its own prefix (--prefix + --ignore-installed) so the
shared ccp4/9.0 module is never modified; PYTHONPATH prepend shadows the
ccp4-bundled copy. ccp4/9.0 is build- and runtime dependency.
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_0152MuuYUaapP7CtxrDAfvBh
