perf(settlement,rating): paginate 3 unbounded list endpoints (M10-M12)

- M10 GET /settlement: was unbounded; add page/limit + countByUser + data.meta.
- M11 GET /admin/comments/pending: paginate findPending + countPending.
- M12 GET /comments/{doctor}: paginate the fetch-joined roots query via
  Paginator(fetchJoinCollection) + countApprovedRootsByDoctor.

All keep the existing { data: { data: [...] } } envelope and add data.meta
(backward compatible). Default limit 50 / max 100.

Regressions: SettlementListPaginationTest, CommentPaginationTest (both fail
without the limits). Also de-flaked SendCodeMobileRateLimitTest (randomised the
IP block so the persistent per-IP limiter buckets don't accumulate across runs).

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

src/Settlement/Repository/SettlementRepository.php

@@ -20,9 +20,14 @@ class SettlementRepository extends ServiceEntityRepository
     }
 
     /** @return Settlement[] */
-    public function findByUser(User $user): array
+    public function findByUser(User $user, int $limit = 50, int $offset = 0): array
     {
-        return $this->findBy(['user' => $user], ['createdAt' => 'DESC']);
+        return $this->findBy(['user' => $user], ['createdAt' => 'DESC'], $limit, $offset);
+    }
+
+    public function countByUser(User $user): int
+    {
+        return $this->count(['user' => $user]);
     }
 
     /** Balance = sum of credits - sum of debits from wallet_transactions */