Show real stats on homepage and real sold counts in event categories

- Homepage: count BilletOrders for tickets sold, sum paid orders for totalHT
- Event categories: count BilletOrders per billet for real sold counts
- Remove placeholder text from tickets stat block

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

src/Controller/AccountController.php

@@ -377,7 +377,7 @@ class AccountController extends AbstractController
             $categoryBillets = $em->getRepository(Billet::class)->findBy(['category' => $category], ['position' => 'ASC']);
             $billets[$category->getId()] = $categoryBillets;
             foreach ($categoryBillets as $billet) {
-                $soldCounts[$billet->getId()] = 0;
+                $soldCounts[$billet->getId()] = $em->getRepository(BilletOrder::class)->count(['billet' => $billet]);
             }
         }