fix(repository): prevent NPE by reversing equals check order in AbstractRepository

- AbstractRepository: fix potential NullPointerException in createMap by calling equals on constant instead of possibly null value to ensure safe comparison when filtering empty properties

Author: TR4E

src/main/java/io/github/trae/database/repository/AbstractRepository.java

@@ -330,7 +330,7 @@ private LinkedHashMap<String, Object> toDataMap(final Domain domain, final List<
         return UtilJava.createMap(new LinkedHashMap<>(), map -> {
             for (final Property property : propertyList) {
                 Object value = domain.getValueByProperty(property);
-                if (value.equals(Constants.EMPTY_PROPERTY)) {
+                if (Constants.EMPTY_PROPERTY.equals(value)) {
                     continue;
                 }