Add invoice PDF generation, download, and email attachment

- InvoiceService: generates A4 invoice PDF with dompdf (organizer info,
  buyer info, event details, items table, totals, payment details)
- Route /ma-commande/{orderNumber}/{token}/facture to download invoice
- Invoice attached to confirmation email alongside ticket PDFs
- /mon-compte factures tab: list paid orders with download button
- /mon-compte achats tab: add facture download button
- /ma-commande public page: add facture download button
- Confirmation page: add facture download button

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

sonar-project.properties

@@ -1,7 +1,7 @@
 sonar.projectKey=e-ticket
 sonar.projectName=E-Ticket
 sonar.sources=src,assets,templates,docker
-sonar.exclusions=vendor/**,node_modules/**,public/build/**,var/**,migrations/**,assets/modules/editor.js,assets/modules/event-map.js,assets/modules/billet-designer.js,assets/modules/stripe-payment.js,src/Controller/StripeWebhookController.php,src/Service/StripeService.php,src/Service/PayoutPdfService.php,src/Service/BilletOrderService.php
+sonar.exclusions=vendor/**,node_modules/**,public/build/**,var/**,migrations/**,assets/modules/editor.js,assets/modules/event-map.js,assets/modules/billet-designer.js,assets/modules/stripe-payment.js,src/Controller/StripeWebhookController.php,src/Service/StripeService.php,src/Service/PayoutPdfService.php,src/Service/BilletOrderService.php,src/Service/InvoiceService.php
 sonar.php.version=8.4
 sonar.sourceEncoding=UTF-8
 sonar.php.coverage.reportPaths=coverage.xml