Complete people-domain move into members app; keep names on Member

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>

members/admin.py

@@ -0,0 +1,62 @@
+from django.contrib import admin
+from django.utils.translation import gettext_lazy as _
+
+from .models import Family, FamilyMembership, Member
+
+
+# Register your models here.
+class MemberFamilyInline(admin.TabularInline):
+    """Family memberships shown on the Member page."""
+
+    model = FamilyMembership
+    extra = 1
+    autocomplete_fields = ("family",)
+
+
+@admin.register(Member)
+class MemberAdmin(admin.ModelAdmin):
+    list_display = ("last_name", "first_name", "contact_email", "phone_display", "emergency_phone_display", "user")
+    list_select_related = ("user",)
+    search_fields = ("first_name", "last_name", "email")
+    autocomplete_fields = ("user",)
+    inlines = [MemberFamilyInline]
+    fields = ("user", "first_name", "last_name", "date_of_birth", "email", "phone", "emergency_phone")
+
+    @admin.display(description=_("email"), ordering="email")
+    def contact_email(self, obj):
+        return obj.contact_email
+
+    @admin.display(description=_("phone"), ordering="phone")
+    def phone_display(self, obj):
+        return obj.phone.as_international if obj.phone else ""
+
+    @admin.display(description=_("emergency phone"), ordering="emergency_phone")
+    def emergency_phone_display(self, obj):
+        return obj.emergency_phone.as_international if obj.emergency_phone else ""
+
+
+class FamilyMemberInline(admin.TabularInline):
+    """Members shown on the Family page."""
+
+    model = FamilyMembership
+    extra = 1
+    autocomplete_fields = ("member",)
+
+
+@admin.register(Family)
+class FamilyAdmin(admin.ModelAdmin):
+    list_display = ("__str__", "member_count")
+    search_fields = ("name", "memberships__member__first_name", "memberships__member__last_name")
+    inlines = [FamilyMemberInline]
+
+    @admin.display(description=_("members"))
+    def member_count(self, obj):
+        return obj.memberships.count()
+
+
+@admin.register(FamilyMembership)
+class FamilyMembershipAdmin(admin.ModelAdmin):
+    list_display = ("family", "member", "role")
+    list_filter = ("role",)
+    autocomplete_fields = ("family", "member")
+    search_fields = ("family__name", "member__first_name", "member__last_name")