Add admin events page with Meilisearch search, KnpPaginator, and navigation link

- Add Evenements link in admin navigation bar
- Create /admin/evenements page with event table (title, organizer, date, city, status, secret)
- Search via Meilisearch event_admin index with fallback to database
- KnpPaginator (10 per page)
- Add 3 tests (success, search, access denied)

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

tests/Controller/AdminControllerTest.php

@@ -595,6 +595,39 @@ class AdminControllerTest extends WebTestCase
         return $user;
     }
 
+    public function testEventsPageReturnsSuccess(): void
+    {
+        $client = static::createClient();
+        $admin = $this->createUser(['ROLE_ROOT']);
+
+        $client->loginUser($admin);
+        $client->request('GET', '/admin/evenements');
+
+        self::assertResponseIsSuccessful();
+    }
+
+    public function testEventsPageWithSearch(): void
+    {
+        $client = static::createClient();
+        $admin = $this->createUser(['ROLE_ROOT']);
+
+        $client->loginUser($admin);
+        $client->request('GET', '/admin/evenements?q=brocante');
+
+        self::assertResponseIsSuccessful();
+    }
+
+    public function testEventsPageDeniedForNonRoot(): void
+    {
+        $client = static::createClient();
+        $user = $this->createUser();
+
+        $client->loginUser($user);
+        $client->request('GET', '/admin/evenements');
+
+        self::assertResponseStatusCodeSame(403);
+    }
+
     private function createOrganizer(EntityManagerInterface $em): User
     {
         $orga = new User();