Finish relocating Member/Family/FamilyMembership from authentication into
a dedicated members app, and revert the half-applied move of member names
onto the global User.
- members: add first_name/last_name back to Member (the whole codebase —
tests, CSV importer, club app, admin — assumes them, and login-less
children in families need a name); restore local ordering/index and the
member__last_name lookups in Family.__str__ and FamilyMembership.
- authentication: drop first_name/last_name from User; get_full_name/
get_short_name delegate to the linked member, else fall back to email.
- migrations: create members.0001_initial, repoint club.ClubMembership FK
(club.0005), delete the models from authentication (0004, rewritten to
plain DeleteModel ops in child-first order to avoid a SQLite table-remake
crash).
- fix stale imports across apps (authentication/club tests, CSV importer)
and missing imports/URLs in members tests; add missing _ import in
members/admin.py; export MemberCsvImporter from members.services.
Full suite green (64 tests), ruff clean.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>