Add parent claims: onboarding a roster of children with no parents on file

The migration path for a club arriving with a list of children from a
federation export and no parent records. Children import without logins, each
into a family of their own -- that shape *is* the "nobody is responsible for
this child" state, so there's no unclaimed flag to drift out of step with
reality, and a family drops off the worklist by itself the moment a parent
joins it. `family_role=child` with a blank `family_group` asks for that; any
other lone role is still a mistake in the file.

Verification is a human decision, deliberately. A parent submits a public form
with the child's name and date of birth as free text -- no search, no
autocomplete, and the same response whether or not the child was found, because
the page needs no login and anything that resolved the child would turn it into
a way to enumerate the club's children. An admin matches it from a queue
against a shortlist that only ever contains children with nobody on file, so
approving can never quietly re-parent a child who already has one.

The alternatives were worse. A claim code needs a delivery channel the club may
not have and is a bearer token besides. Matching on name plus birthday hands out
someone else's child to whoever guesses a birthday. The club is the only party
that actually knows its own families.

That form is also the registration: open self-registration is now closed
(shadowing account_signup rather than removing the route, so the URL name
allauth's templates reverse still resolves). The account is created on
approval, not on submission, so a public form can't fill the user table. An
approved parent lands as a guardian -- login and family link, no membership, no
fee -- gets a password-reset link, and a minimal "my family" page.

One bug worth recording: families_awaiting_a_parent first used
annotate(Count(..., filter=...)) over a queryset already filtered on the same
join, so Django reused that join for the counts and a parent with no
ClubMembership of their own -- exactly what a newly linked guardian is -- went
uncounted, leaving the family unclaimed forever. Exists subqueries avoid it. A
test pins both directions.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

members/admin.py

@@ -1,7 +1,7 @@
 from django.contrib import admin
 from django.utils.translation import gettext_lazy as _
 
-from .models import Family, FamilyMembership, Group, GroupMembership, Member
+from .models import Family, FamilyMembership, Group, GroupMembership, Member, ParentClaim
 
 
 # Register your models here.
@@ -87,3 +87,17 @@ class GroupMembershipAdmin(admin.ModelAdmin):
     list_display = ("group", "member")
     autocomplete_fields = ("group", "member")
     search_fields = ("group__name", "member__first_name", "member__last_name")
+
+
+@admin.register(ParentClaim)
+class ParentClaimAdmin(admin.ModelAdmin):
+    """Read-mostly: approving belongs in the club's own review queue
+    (management.views.ParentClaimListView), which links the family and creates the
+    account as one atomic step. Flipping `status` here would leave a claim marked
+    approved with nothing actually linked."""
+
+    list_display = ("parent_name", "claimed_child_name", "club", "status", "reviewed_by", "created")
+    list_filter = ("club", "status")
+    search_fields = ("parent_first_name", "parent_last_name", "parent_email", "child_first_name", "child_last_name")
+    raw_id_fields = ("child", "reviewed_by")
+    readonly_fields = ("created", "modified")