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>

teams/migrations/0009_team_referee_management.py

@@ -0,0 +1,18 @@
+# Generated by Django 6.0.6 on 2026-08-09 10:00
+
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('teams', '0008_refereelevel_refereeprofile_and_more'),
+    ]
+
+    operations = [
+        migrations.AddField(
+            model_name='team',
+            name='referee_management',
+            field=models.CharField(choices=[('club', 'Club'), ('federation', 'Federation')], default='club', help_text="Who arranges referees for this team's home games. Federation-managed teams are left out of the referee tools entirely -- no eligibility, no assignment, nothing to configure.", max_length=20, verbose_name='referee management'),
+        ),
+    ]