Add RegionStorage class with persistence delegation

src/main/java/com/livingworld/regions/RegionStorage.java

@@ -0,0 +1,56 @@
+package com.livingworld.regions;
+
+import com.livingworld.core.services.PersistenceService;
+
+import java.util.Optional;
+
+/**
+ * Storage class for managing region persistence operations.
+ *
+ * <p>This class delegates loading and saving of regions to the provided
+ * {@link PersistenceService} instance, with argument validation.</p>
+ */
+public class RegionStorage {
+
+    private final PersistenceService persistenceService;
+
+    /**
+     * Creates a new RegionStorage instance.
+     *
+     * @param persistenceService the persistence service to delegate to (must not be null)
+     * @throws IllegalArgumentException if persistenceService is null
+     */
+    public RegionStorage(PersistenceService persistenceService) {
+        if (persistenceService == null) {
+            throw new IllegalArgumentException("PersistenceService must not be null");
+        }
+        this.persistenceService = persistenceService;
+    }
+
+    /**
+     * Loads a region from storage by its coordinate.
+     *
+     * @param coordinate the region coordinate to load (must not be null)
+     * @return an Optional containing the loaded region if it exists, or empty if not found
+     * @throws IllegalArgumentException if coordinate is null
+     */
+    public Optional<Region> load(RegionCoordinate coordinate) {
+        if (coordinate == null) {
+            throw new IllegalArgumentException("RegionCoordinate must not be null");
+        }
+        return persistenceService.loadRegion(coordinate);
+    }
+
+    /**
+     * Saves a region to storage.
+     *
+     * @param region the region to save (must not be null)
+     * @throws IllegalArgumentException if region is null
+     */
+    public void save(Region region) {
+        if (region == null) {
+            throw new IllegalArgumentException("Region must not be null");
+        }
+        persistenceService.saveRegion(region);
+    }
+}