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>

management/templates/management/group_form.html

@@ -0,0 +1,35 @@
+{% extends "management/base.html" %}
+{% load i18n lucide static ui %}
+
+{% block heading %}{% if update_view %}{% blocktrans %}Edit {{ object }}{% endblocktrans %}{% else %}{% trans "New group" %}{% endif %}{% endblock heading %}
+
+{% block panel %}
+    <div class="card w-full bg-base-100 shadow">
+        <div class="card-body">
+            <form method="post">
+                {% csrf_token %}
+
+                {% for error in form.non_field_errors %}
+                    <div class="alert alert-error my-2">
+                        <span>{{ error }}</span>
+                    </div>
+                {% endfor %}
+
+                <div class="grid grid-cols-1 md:grid-cols-2 gap-4">
+                    {% for field in form %}
+                        {% form_field field %}
+                    {% endfor %}
+                </div>
+
+                <div class="card-actions justify-start pt-2 mt-2">
+                    <a class="btn btn-outline gap-2" href="{% if update_view %}{% url "management:group_detail" object.pk %}{% else %}{% url "management:group_list" %}{% endif %}">{% lucide "arrow-left" size=16 %} {% trans "Cancel" %}</a>
+                    <button class="btn btn-primary gap-2" type="submit">{% lucide "save" size=16 %} {% trans "Save" %}</button>
+                </div>
+            </form>
+        </div>
+    </div>
+{% endblock panel %}
+
+{% block extra_body %}
+    <script src="{% static 'js/searchable-select.js' %}"></script>
+{% endblock extra_body %}