performance: Caching, deferred Tracking & externe Timeouts (H7, M12, M13)

- Navigations-Chrome (CategoryNavigation), Suche- und Newsroom-Seitendaten
  300s gecacht; gemeinsamer WebPageCache-Helper (eine TTL/Key-Konvention).
- Cache-Poisoning über ?page= geschlossen (Key an Paginator ausgerichtet,
  kein withQueryString im Cache); Newsrooms cachet nur den ungefilterten
  Fall und die ersten Seiten (kein unbegrenzter Key-Raum).
- Detailseiten schreiben Hits/View-Events deferred nach der Response
  (M12); OpenAI-/Markt-/USt-ID-Aufrufe mit Connect-Timeouts und
  begrenzten Retries; Admin-Memo-Caches konsistent invalidiert.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

tests/Feature/ReviewCheckServiceTest.php

@@ -49,6 +49,25 @@ test('once the free quota is empty the overflow draws one credit per check', fun
     expect($this->wallet->balance($user))->toBe(4);
 });
 
+test('stale user instances cannot consume the same final free review check', function () {
+    $user = User::factory()->create();
+    $this->wallet->credit($user, 5);
+
+    for ($i = 0; $i < 3; $i++) {
+        $this->service->recordCheck($user);
+    }
+
+    $firstRequestUser = $user->fresh();
+    $secondRequestUser = $user->fresh();
+
+    $lastFreeCheck = $this->service->recordCheck($firstRequestUser);
+    $overflowCheck = $this->service->recordCheck($secondRequestUser);
+
+    expect($lastFreeCheck->source)->toBe(ReviewCheckSource::Free)
+        ->and($overflowCheck->source)->toBe(ReviewCheckSource::Credit)
+        ->and($this->wallet->balance($user))->toBe(4);
+});
+
 test('overflow without enough credits throws and records nothing', function () {
     $user = User::factory()->create();
     for ($i = 0; $i < 4; $i++) {