Add invoice cancelled status, treasury event name, and voucher number backfill.

EOF

Co-authored-by: Cursor <cursoragent@cursor.com>

accounting/migrations/0007_backfill_voucher_numbers.py

@@ -0,0 +1,31 @@
+from django.db import migrations
+
+
+def backfill_voucher_numbers(apps, schema_editor):
+    Voucher = apps.get_model('accounting', 'Voucher')
+
+    max_number = (
+        Voucher.objects.exclude(number__lte=0)
+        .order_by('-number')
+        .values_list('number', flat=True)
+        .first()
+        or 0
+    )
+
+    missing_number_vouchers = Voucher.objects.filter(number__lte=0).order_by('created_at', 'id')
+
+    next_number = max_number + 1
+    for voucher in missing_number_vouchers:
+        voucher.number = next_number
+        voucher.save(update_fields=['number'])
+        next_number += 1
+
+
+class Migration(migrations.Migration):
+    dependencies = [
+        ('accounting', '0006_treasury_fee_fields'),
+    ]
+
+    operations = [
+        migrations.RunPython(backfill_voucher_numbers, migrations.RunPython.noop),
+    ]