Add referee assignment/eligibility system, team bulk-add, member Groups, and referee management dashboard with PDF export

Builds the referee workflow end to end: club-defined RefereeLevel/RefereeProfile
eligibility tied to teams, EventReferee assignment (member or external, with
fee/km payment tracking), an admin dashboard with KPI tiles, date-grouped game
tiles and range filters, and a downloadable payment form PDF modeled on the
club's existing paper document (using Club.legal_name when set). Also lands
team roster bulk-add, member mass-upload with family linking, and the
members.Group model, developed alongside this work.

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

members/migrations/0004_group_groupmembership_and_more.py

@@ -0,0 +1,54 @@
+# Generated by Django 6.0.6 on 2026-08-08 21:53
+
+import django.db.models.deletion
+import uuid
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('club', '0020_sponsor_logo_height_sponsor_logo_width'),
+        ('members', '0003_family_created_family_modified_member_created_and_more'),
+    ]
+
+    operations = [
+        migrations.CreateModel(
+            name='Group',
+            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)),
+                ('name', models.CharField(max_length=255, verbose_name='name')),
+                ('club', models.ForeignKey(on_delete=django.db.models.deletion.CASCADE, related_name='%(class)ss', to='club.club')),
+            ],
+            options={
+                'verbose_name': 'group',
+                'verbose_name_plural': 'groups',
+                'ordering': ['name'],
+            },
+        ),
+        migrations.CreateModel(
+            name='GroupMembership',
+            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)),
+                ('group', models.ForeignKey(on_delete=django.db.models.deletion.CASCADE, related_name='memberships', to='members.group', verbose_name='group')),
+                ('member', models.ForeignKey(on_delete=django.db.models.deletion.CASCADE, related_name='group_memberships', to='members.member', verbose_name='member')),
+            ],
+            options={
+                'verbose_name': 'group membership',
+                'verbose_name_plural': 'group memberships',
+                'ordering': ['group', 'member__last_name', 'member__first_name'],
+            },
+        ),
+        migrations.AddConstraint(
+            model_name='group',
+            constraint=models.UniqueConstraint(fields=('club', 'name'), name='unique_group_name_per_club'),
+        ),
+        migrations.AddConstraint(
+            model_name='groupmembership',
+            constraint=models.UniqueConstraint(fields=('group', 'member'), name='unique_member_per_group'),
+        ),
+    ]