Make invoice emitter configurable via environment variables

Add environment variables for invoice company details to allow customization without code changes. Update invoice view and Stripe service to use these configurable values.

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <noreply@anthropic.com>

app/services/stripe_invoice_service.rb

@@ -103,7 +103,7 @@ class StripeInvoiceService
       name: customer_name,
       metadata: {
         user_id: @order.user.id,
-        created_by: "aperonight_system"
+        created_by: "#{ENV.fetch('INVOICE_COMPANY_NAME', 'aperonight').downcase}_system"
       }
     })
 
@@ -133,7 +133,7 @@ class StripeInvoiceService
         order_id: @order.id,
         user_id: @order.user.id,
         event_name: @order.event.name,
-        created_by: "aperonight_system",
+        created_by: "#{ENV.fetch('INVOICE_COMPANY_NAME', 'aperonight').downcase}_system",
         payment_method: "checkout_session"
       },
       description: "Invoice for #{@order.event.name} - Order ##{@order.id}",