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/migrations/0005_parent_claim.py

@@ -0,0 +1,41 @@
+# Generated by Django 6.0.6 on 2026-08-11 14:22
+
+import django.db.models.deletion
+import uuid
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('club', '0023_backfill_guardian_memberships'),
+        ('members', '0004_group_groupmembership_and_more'),
+    ]
+
+    operations = [
+        migrations.CreateModel(
+            name='ParentClaim',
+            fields=[
+                ('created', models.DateTimeField(auto_now_add=True, verbose_name='created')),
+                ('modified', models.DateTimeField(auto_now=True, verbose_name='modified')),
+                ('id', models.UUIDField(default=uuid.uuid4, editable=False, primary_key=True, serialize=False)),
+                ('parent_first_name', models.CharField(max_length=150, verbose_name='parent first name')),
+                ('parent_last_name', models.CharField(max_length=150, verbose_name='parent last name')),
+                ('parent_email', models.EmailField(max_length=254, verbose_name='parent email')),
+                ('child_first_name', models.CharField(max_length=150, verbose_name='child first name')),
+                ('child_last_name', models.CharField(max_length=150, verbose_name='child last name')),
+                ('child_date_of_birth', models.DateField(verbose_name='child date of birth')),
+                ('status', models.CharField(choices=[('pending', 'pending'), ('approved', 'approved'), ('rejected', 'rejected')], default='pending', max_length=20, verbose_name='status')),
+                ('reviewed_at', models.DateTimeField(blank=True, null=True, verbose_name='reviewed at')),
+                ('note', models.TextField(blank=True, help_text='Why it was rejected, or anything worth recording about the decision.', verbose_name='note')),
+                ('child', models.ForeignKey(blank=True, help_text='Set when an admin approves the claim -- the child it was matched to.', null=True, on_delete=django.db.models.deletion.SET_NULL, related_name='parent_claims', to='members.member', verbose_name='matched child')),
+                ('club', models.ForeignKey(on_delete=django.db.models.deletion.CASCADE, related_name='%(class)ss', to='club.club')),
+                ('reviewed_by', models.ForeignKey(blank=True, null=True, on_delete=django.db.models.deletion.SET_NULL, related_name='+', to='members.member', verbose_name='reviewed by')),
+            ],
+            options={
+                'verbose_name': 'parent claim',
+                'verbose_name_plural': 'parent claims',
+                'ordering': ['-created'],
+            },
+        ),
+    ]