Workflow now targets Simone/nsis-plugin-ns7zip. Renamed the file and
the workflow `name:`, and updated all references in active docs
(plans/archived and docs/archived left as frozen history).
Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>
Update active docs (PhaseA/B checklists, README) after rename of feature/python-rewrite-phase-a -> feature/python-rewrite-and-linux-migration. Historical A1-A5 closeouts left untouched as they document state at the time of writing.