NCBACK-34 add logic to find similar image in db

src/main/java/ru/soune/nocopy/service/file/FileUploadServiceImpl.java

@@ -402,7 +402,7 @@ public class FileUploadServiceImpl implements FileUploadService {
                 session.getUploadId(), session.getFileName());
 
         Path finalFilePath = null;
-        String checksum = null;
+        String checksum;
 
         try {
             finalFilePath = prepareFinalFile(session);
@@ -591,44 +591,10 @@ public class FileUploadServiceImpl implements FileUploadService {
     private void handleAssemblyFailure(FileUploadSession session, Exception e) {
         session.setStatus(UploadStatus.FAILED);
         session.setLastError(e.getMessage());
+
         sessionRepository.save(session);
-
-        log.error("File assembly failed for session {}: {}",
-                session.getUploadId(), e.getMessage());
     }
 
-
-
-//    @Override
-//    @Transactional
-//    public void cleanupExpiredSessions() {
-//        log.info("Starting cleanup of expired upload sessions");
-//
-//        LocalDateTime expiryThreshold = LocalDateTime.now().minusHours(sessionExpiryHours);
-//
-//        try {
-//            var expiredSessions = sessionRepository.findByStatusInAndCreatedAtBefore(
-//                    Set.of(UploadStatus.INITIATED, UploadStatus.UPLOADING, UploadStatus.FAILED),
-//                    expiryThreshold
-//            );
-//
-//            int cleanedCount = 0;
-//            for (FileUploadSession session : expiredSessions) {
-//                session.setStatus(UploadStatus.FAILED);
-//                session.setLastError("Session expired during cleanup");
-//                sessionRepository.save(session);
-//
-//                CompletableFuture.runAsync(() -> cleanupSessionFiles(session));
-//                cleanedCount++;
-//            }
-//
-//            log.info("Cleaned up {} expired upload sessions", cleanedCount);
-//
-//        } catch (Exception e) {
-//            log.error("Error during session cleanup", e);
-//        }
-//    }
-
     private Path getChunkDirectory(Long userId, String uploadId) {
         return storageRoot.resolve("temp")
                 .resolve("user")