Checkpoint: management app redesign, onboarding/signup workflow, and events calendar backend

Large uncommitted body of work accumulated across sessions on this branch --
committing as a checkpoint so it's tracked and future worktree-isolated agents
see the real codebase instead of a stale ancestor commit. Covers the
management app's dedicated Tailwind theme and templates, the club onboarding
requirement/signup workflow (club/services/onboarding.py, requirement/status
models, sign-up dashboard), fee/status auto-activation decoupling, referee
management, and the new events calendar grid service layer.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01ECGMEwrc2k4D8VQuwjstj9

teams/migrations/0010_alter_team_options_alter_teammembership_position.py

@@ -0,0 +1,23 @@
+# Generated by Django 6.0.6 on 2026-08-17 17:49
+
+import django.db.models.deletion
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('teams', '0009_team_referee_management'),
+    ]
+
+    operations = [
+        migrations.AlterModelOptions(
+            name='team',
+            options={'ordering': ['name'], 'verbose_name': 'team', 'verbose_name_plural': 'teams'},
+        ),
+        migrations.AlterField(
+            model_name='teammembership',
+            name='position',
+            field=models.ForeignKey(blank=True, help_text="Left blank for a member placed on the roster before their position is decided (e.g. from the Sign-up page) -- the team's own manager sets it once known.", limit_choices_to={'staff_position': False}, null=True, on_delete=django.db.models.deletion.PROTECT, related_name='team_memberships', to='teams.position', verbose_name='position'),
+        ),
+    ]