Consolidate persistence service contract

src/main/java/com/livingworld/core/services/CoreServices.java

@@ -1,6 +1,5 @@
 package com.livingworld.core.services;
 
-import com.livingworld.core.simulation.PersistenceService;
 import com.livingworld.core.simulation.RegionManager;
 import com.livingworld.core.simulation.SimulationManager;
 import com.livingworld.events.LivingWorldEventBus;

src/main/java/com/livingworld/core/simulation/PersistenceService.java

@@ -1,39 +0,0 @@
-package com.livingworld.core.simulation;
-
-import java.util.Optional;
-
-import com.livingworld.regions.Region;
-import com.livingworld.regions.RegionCoordinate;
-
-/**
- * Handles region persistence (save/load) and migration support.
- * 
- * <p><b>TODO (Milestone 8):</b> Implement actual file or database I/O,
- * platform-specific save paths, and schema versioning.</p>
- */
-public interface PersistenceService {
-
-    /**
-     * Saves a region to persistent storage.
-     * 
-     * @param region the region to save (must not be null)
-     */
-    void save(Region region);
-
-    /**
-     * Loads a region from persistent storage.
-     * 
-     * @param coordinate the region coordinate to load (must not be null)
-     * @return an optional containing the loaded region if found, otherwise empty
-     */
-    Optional<Region> load(RegionCoordinate coordinate);
-
-    /**
-     * Returns whether this persistence service supports data migration.
-     * 
-     * <p><b>TODO:</b> Implement schema version detection and migration logic.</p>
-     * 
-     * @return true if migration is supported
-     */
-    boolean supportsMigration();
-}

src/main/java/com/livingworld/core/simulation/SimulationManager.java

@@ -4,6 +4,7 @@ import java.util.List;
 import java.util.Optional;
 import java.util.Set;
 
+import com.livingworld.core.services.PersistenceService;
 import com.livingworld.core.services.TimeService;
 import com.livingworld.debug.DiagnosticCategory;
 import com.livingworld.debug.LivingWorldLogger;

src/test/java/com/livingworld/core/simulation/SimulationManagerTest.java

@@ -17,6 +17,7 @@ import java.util.Set;
 import org.junit.jupiter.api.Test;
 
 import com.livingworld.config.SimulationConfig;
+import com.livingworld.core.services.PersistenceService;
 import com.livingworld.core.services.TimeService;
 import com.livingworld.data.serialization.PersistenceReader;
 import com.livingworld.data.serialization.PersistenceWriter;
@@ -240,9 +241,13 @@ class SimulationManagerTest {
     }
 
     private static final class TestPersistenceService implements PersistenceService {
-        @Override public void save(Region region) {}
-        @Override public Optional<Region> load(RegionCoordinate coordinate) { return Optional.empty(); }
-        @Override public boolean supportsMigration() { return false; }
+        @Override public void markRegionDirty(Region region) { region.markDirty(); }
+        @Override public void saveDirtyRegions() {}
+        @Override public void saveRegion(Region region) {}
+        @Override public Optional<Region> loadRegion(RegionCoordinate coordinate) {
+            return Optional.empty();
+        }
+        @Override public void flushAll() {}
     }
 
     private static final class TestProfiler implements SimulationProfiler {

src/test/java/com/livingworld/testing/LongRunSimulationTest.java

@@ -5,9 +5,9 @@ import static org.junit.jupiter.api.Assertions.assertFalse;
 import static org.junit.jupiter.api.Assertions.assertTrue;
 
 import com.livingworld.config.SimulationConfig;
+import com.livingworld.core.services.PersistenceService;
 import com.livingworld.core.services.ServiceRegistry;
 import com.livingworld.core.simulation.DefaultTimeService;
-import com.livingworld.core.simulation.PersistenceService;
 import com.livingworld.core.simulation.RegionManager;
 import com.livingworld.core.simulation.RegionUpdateJob;
 import com.livingworld.core.simulation.SimulationManager;
@@ -174,11 +174,12 @@ class LongRunSimulationTest {
             this.regions = regions;
         }
 
-        private void saveDirtyRegions() {
+        @Override
+        public void saveDirtyRegions() {
             maxDirtyObserved = Math.max(maxDirtyObserved, countDirtyRegions());
             regions.stream()
                     .filter(Region::isDirty)
-                    .forEach(this::save);
+                    .forEach(this::saveRegion);
         }
 
         private int countDirtyRegions() {
@@ -194,20 +195,25 @@ class LongRunSimulationTest {
         }
 
         @Override
-        public void save(Region region) {
+        public void markRegionDirty(Region region) {
+            region.markDirty();
+        }
+
+        @Override
+        public void saveRegion(Region region) {
             savedRegions.put(region.getCoordinate(), region);
             region.clearDirty();
             saveCount++;
         }
 
         @Override
-        public Optional<Region> load(RegionCoordinate coordinate) {
+        public Optional<Region> loadRegion(RegionCoordinate coordinate) {
             return Optional.ofNullable(savedRegions.get(coordinate));
         }
 
         @Override
-        public boolean supportsMigration() {
-            return false;
+        public void flushAll() {
+            saveDirtyRegions();
         }
     }
 }