fix(aria): fix os_eol_status enum cast — use native SQL throughout

PostgreSQL named enum types require explicit casts that Hibernate's
derived query methods don't generate. Replace countByOsEolStatus and
findByOsEolStatusOrderByPostureScoreAsc with native @Query variants that
CAST(:status AS os_eol_status). Same pattern already applied to severity.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

src/main/java/com/hiveops/aria/controller/DevicePostureController.java

@@ -52,7 +52,7 @@ public class DevicePostureController {
         Pageable pageable = PageRequest.of(page, size);
 
         if (osEolStatus != null) {
-            return postureRepository.findByOsEolStatusOrderByPostureScoreAsc(osEolStatus, pageable);
+            return postureRepository.findByOsEolStatusNativeOrderByPostureScoreAsc(osEolStatus.name(), pageable);
         }
         if ("low".equals(scoreFilter)) {
             return postureRepository.findByPostureScoreLessThanOrderByPostureScoreAsc(50, pageable);