feat(billing): EN16931 + Romanian law PDF compliance (#153)

services/platform/apps/billing/invoice_models.py

@@ -134,6 +134,7 @@ class Invoice(models.Model):
     # Billing address snapshot (immutable once issued)
     bill_to_name = models.CharField(max_length=255, default="")
     bill_to_tax_id = models.CharField(max_length=50, blank=True)
+    bill_to_registration_number = models.CharField(max_length=50, blank=True)  # Nr. Reg. Com. / J number
     bill_to_email = models.EmailField(blank=True)
     bill_to_address1 = models.CharField(max_length=255, blank=True)
     bill_to_address2 = models.CharField(max_length=255, blank=True)

services/platform/apps/billing/migrations/0025_add_bill_to_registration_number.py

@@ -0,0 +1,21 @@
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ("billing", "0024_backfill_refunds_from_meta"),
+    ]
+
+    operations = [
+        migrations.AddField(
+            model_name="invoice",
+            name="bill_to_registration_number",
+            field=models.CharField(blank=True, max_length=50),
+        ),
+        migrations.AddField(
+            model_name="proformainvoice",
+            name="bill_to_registration_number",
+            field=models.CharField(blank=True, max_length=50),
+        ),
+    ]