feat(billing): add missing payment methods and configurations

- Added migration to include global payment method configurations for Stripe and PayPal (both disabled).
- Ensured existing payment methods like bank transfer and manual payment are correctly configured.
- Added database constraints and indexes for improved data integrity in billing models.
- Introduced foreign key relationship between CreditTransaction and Payment models.
- Added webhook configuration fields to PaymentMethodConfig for future payment gateway integrations.
- Updated SignUpFormUnified component to handle payment method selection based on user country and plan.
- Implemented PaymentHistory component to display user's payment history with status indicators.

backend/igny8_core/modules/billing/migrations/0008_add_invoice_subscription_fk.py

@@ -0,0 +1,84 @@
+# Generated migration to add subscription FK to Invoice and fix Payment status default
+from django.db import migrations, models
+import django.db.models.deletion
+
+
+def populate_subscription_from_metadata(apps, schema_editor):
+    """Populate subscription FK from metadata for existing invoices"""
+    # Use raw SQL to avoid model field issues during migration
+    from django.db import connection
+    
+    with connection.cursor() as cursor:
+        # Get invoices with subscription_id in metadata
+        cursor.execute("""
+            SELECT id, metadata 
+            FROM igny8_invoices 
+            WHERE metadata::text LIKE '%subscription_id%'
+        """)
+        
+        updated_count = 0
+        for invoice_id, metadata in cursor.fetchall():
+            if metadata and isinstance(metadata, dict) and 'subscription_id' in metadata:
+                try:
+                    sub_id = int(metadata['subscription_id'])
+                    # Check if subscription exists
+                    cursor.execute(
+                        "SELECT id FROM igny8_subscriptions WHERE id = %s",
+                        [sub_id]
+                    )
+                    if cursor.fetchone():
+                        # Update invoice with subscription FK
+                        cursor.execute(
+                            "UPDATE igny8_invoices SET subscription_id = %s WHERE id = %s",
+                            [sub_id, invoice_id]
+                        )
+                        updated_count += 1
+                except (ValueError, KeyError) as e:
+                    print(f"Could not populate subscription for invoice {invoice_id}: {e}")
+        
+        print(f"Populated subscription FK for {updated_count} invoices")
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('billing', '0007_simplify_payment_statuses'),
+        ('igny8_core_auth', '0011_remove_subscription_payment_method'),
+    ]
+
+    operations = [
+        # Add subscription FK to Invoice
+        migrations.AddField(
+            model_name='invoice',
+            name='subscription',
+            field=models.ForeignKey(
+                blank=True,
+                help_text='Subscription this invoice is for (if subscription-based)',
+                null=True,
+                on_delete=django.db.models.deletion.SET_NULL,
+                related_name='invoices',
+                to='igny8_core_auth.subscription'
+            ),
+        ),
+        # Populate data
+        migrations.RunPython(
+            populate_subscription_from_metadata,
+            reverse_code=migrations.RunPython.noop
+        ),
+        # Fix Payment status default
+        migrations.AlterField(
+            model_name='payment',
+            name='status',
+            field=models.CharField(
+                choices=[
+                    ('pending_approval', 'Pending Approval'),
+                    ('succeeded', 'Succeeded'),
+                    ('failed', 'Failed'),
+                    ('refunded', 'Refunded')
+                ],
+                db_index=True,
+                default='pending_approval',
+                max_length=20
+            ),
+        ),
+    ]

backend/igny8_core/modules/billing/migrations/0009_add_missing_payment_methods.py

@@ -0,0 +1,80 @@
+# Migration to add missing payment method configurations
+from django.db import migrations
+
+
+def add_missing_payment_methods(apps, schema_editor):
+    """Add stripe and paypal global configs (disabled) and ensure all configs exist"""
+    PaymentMethodConfig = apps.get_model('billing', 'PaymentMethodConfig')
+    
+    # Add global Stripe (disabled - waiting for integration)
+    PaymentMethodConfig.objects.get_or_create(
+        country_code='*',
+        payment_method='stripe',
+        defaults={
+            'is_enabled': False,
+            'display_name': 'Credit/Debit Card (Stripe)',
+            'instructions': 'Stripe payment integration coming soon.',
+            'sort_order': 1
+        }
+    )
+    
+    # Add global PayPal (disabled - waiting for integration)
+    PaymentMethodConfig.objects.get_or_create(
+        country_code='*',
+        payment_method='paypal',
+        defaults={
+            'is_enabled': False,
+            'display_name': 'PayPal',
+            'instructions': 'PayPal payment integration coming soon.',
+            'sort_order': 2
+        }
+    )
+    
+    # Ensure global bank_transfer exists with good instructions
+    PaymentMethodConfig.objects.get_or_create(
+        country_code='*',
+        payment_method='bank_transfer',
+        defaults={
+            'is_enabled': True,
+            'display_name': 'Bank Transfer',
+            'instructions': 'Bank transfer details will be provided after registration.',
+            'sort_order': 3
+        }
+    )
+    
+    # Add manual payment as global option
+    PaymentMethodConfig.objects.get_or_create(
+        country_code='*',
+        payment_method='manual',
+        defaults={
+            'is_enabled': True,
+            'display_name': 'Manual Payment (Contact Support)',
+            'instructions': 'Contact support@igny8.com for manual payment arrangements.',
+            'sort_order': 10
+        }
+    )
+    
+    print("Added/updated payment method configurations")
+
+
+def remove_added_payment_methods(apps, schema_editor):
+    """Reverse migration"""
+    PaymentMethodConfig = apps.get_model('billing', 'PaymentMethodConfig')
+    PaymentMethodConfig.objects.filter(
+        country_code='*',
+        payment_method__in=['stripe', 'paypal', 'manual']
+    ).delete()
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('billing', '0008_add_invoice_subscription_fk'),
+    ]
+
+    operations = [
+        migrations.RunPython(
+            add_missing_payment_methods,
+            reverse_code=remove_added_payment_methods
+        ),
+    ]

backend/igny8_core/modules/billing/migrations/0010_add_database_constraints.py

@@ -0,0 +1,58 @@
+# Migration to add database constraints and indexes for data integrity
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('billing', '0009_add_missing_payment_methods'),
+        ('igny8_core_auth', '0011_remove_subscription_payment_method'),
+    ]
+
+    operations = [
+        # Add DB index on invoice_number for fast lookups
+        migrations.AlterField(
+            model_name='invoice',
+            name='invoice_number',
+            field=models.CharField(db_index=True, max_length=50, unique=True),
+        ),
+        
+        # Add index on Payment.status for filtering
+        migrations.AlterField(
+            model_name='payment',
+            name='status',
+            field=models.CharField(
+                choices=[
+                    ('pending_approval', 'Pending Approval'),
+                    ('succeeded', 'Succeeded'),
+                    ('failed', 'Failed'),
+                    ('refunded', 'Refunded')
+                ],
+                db_index=True,
+                default='pending_approval',
+                max_length=20
+            ),
+        ),
+        
+        # Add partial unique index on AccountPaymentMethod for single default per account
+        # This prevents multiple is_default=True per account
+        migrations.RunSQL(
+            sql="""
+                CREATE UNIQUE INDEX billing_account_payment_method_single_default 
+                ON igny8_account_payment_methods (tenant_id) 
+                WHERE is_default = true AND is_enabled = true;
+            """,
+            reverse_sql="""
+                DROP INDEX IF EXISTS billing_account_payment_method_single_default;
+            """
+        ),
+        
+        # Add composite index on Payment for common queries
+        migrations.AddIndex(
+            model_name='payment',
+            index=models.Index(
+                fields=['account', 'status', '-created_at'],
+                name='payment_account_status_created_idx'
+            ),
+        ),
+    ]

backend/igny8_core/modules/billing/migrations/0011_add_manual_reference_constraint.py

@@ -0,0 +1,25 @@
+# Generated migration to add payment constraints
+
+from django.db import migrations
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('billing', '0010_add_database_constraints'),
+    ]
+
+    operations = [
+        # Add composite unique constraint on manual_reference + tenant_id
+        # This prevents duplicate payment submissions with same reference for an account
+        migrations.RunSQL(
+            sql="""
+            CREATE UNIQUE INDEX billing_payment_manual_ref_account_unique 
+            ON igny8_payments(tenant_id, manual_reference) 
+            WHERE manual_reference != '' AND manual_reference IS NOT NULL;
+            """,
+            reverse_sql="""
+            DROP INDEX IF EXISTS billing_payment_manual_ref_account_unique;
+            """
+        ),
+    ]

backend/igny8_core/modules/billing/migrations/0012_add_payment_fk_to_credit_transaction.py

@@ -0,0 +1,44 @@
+# Generated migration to add Payment FK to CreditTransaction
+
+from django.db import migrations, models
+import django.db.models.deletion
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('billing', '0011_add_manual_reference_constraint'),
+    ]
+
+    operations = [
+        # Add payment FK field
+        migrations.AddField(
+            model_name='credittransaction',
+            name='payment',
+            field=models.ForeignKey(
+                blank=True,
+                null=True,
+                on_delete=django.db.models.deletion.SET_NULL,
+                related_name='credit_transactions',
+                to='billing.payment',
+                help_text='Payment that triggered this credit transaction'
+            ),
+        ),
+        
+        # Migrate existing reference_id data to payment FK
+        migrations.RunSQL(
+            sql="""
+            UPDATE igny8_credit_transactions ct
+            SET payment_id = (
+                SELECT id FROM igny8_payments p 
+                WHERE p.id::text = ct.reference_id 
+                AND ct.reference_id ~ '^[0-9]+$'
+                LIMIT 1
+            )
+            WHERE ct.reference_id IS NOT NULL 
+            AND ct.reference_id != ''
+            AND ct.reference_id ~ '^[0-9]+$';
+            """,
+            reverse_sql=migrations.RunSQL.noop
+        ),
+    ]

backend/igny8_core/modules/billing/migrations/0013_add_webhook_config.py

@@ -0,0 +1,49 @@
+# Generated migration to add webhook fields to PaymentMethodConfig
+
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('billing', '0012_add_payment_fk_to_credit_transaction'),
+    ]
+
+    operations = [
+        # Add webhook configuration fields
+        migrations.AddField(
+            model_name='paymentmethodconfig',
+            name='webhook_url',
+            field=models.URLField(
+                blank=True,
+                help_text='Webhook URL for payment gateway callbacks (Stripe/PayPal)'
+            ),
+        ),
+        migrations.AddField(
+            model_name='paymentmethodconfig',
+            name='webhook_secret',
+            field=models.CharField(
+                max_length=255,
+                blank=True,
+                help_text='Webhook secret for signature verification'
+            ),
+        ),
+        migrations.AddField(
+            model_name='paymentmethodconfig',
+            name='api_key',
+            field=models.CharField(
+                max_length=255,
+                blank=True,
+                help_text='API key for payment gateway integration'
+            ),
+        ),
+        migrations.AddField(
+            model_name='paymentmethodconfig',
+            name='api_secret',
+            field=models.CharField(
+                max_length=255,
+                blank=True,
+                help_text='API secret for payment gateway integration'
+            ),
+        ),
+    ]