feat: Add event co-managers permissions and allow managers/admins to signup guests on skill-restricted shifts

backend/apps/events/migrations/0005_event_co_managers.py

@@ -0,0 +1,20 @@
+# Generated by Django 6.0.7 on 2026-07-31 09:05
+
+from django.conf import settings
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('events', '0004_shift_date'),
+        migrations.swappable_dependency(settings.AUTH_USER_MODEL),
+    ]
+
+    operations = [
+        migrations.AddField(
+            model_name='event',
+            name='co_managers',
+            field=models.ManyToManyField(blank=True, help_text='Weitere Verwalter dieser Veranstaltung', related_name='managed_events', to=settings.AUTH_USER_MODEL),
+        ),
+    ]