Add a 'Python packages' button to the file-tree toolbar that opens a modal to
edit the project's requirements.vrf (one package per line, pip syntax), backed
by GET/POST /project/:id/python-requirements (read via ProjectEntityHandler,
write via EditorController.upsertDocWithPath, write-gated). The .vrf file is now
hidden from the file tree, so it is managed only through this editor rather than
appearing as a loose file. Adds python_packages / python_packages_help i18n.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
claude