fix(07-13): clear existing dynamic tiles before loading

- add private clearDynamics() that snapshots the managed dynamic tiles and drops each via the deleteDynamic semantics (syncStaticEvent + removeTile + onDeleteDynamic), without awaiting the hook
- call it as the first line of loadState so all three compression tiers and the missing-dynamicBlocks case start from a clean slate (#06-17-8)
- add regressions: mapLayer hook/instance witness and the three-tier repeated-load non-accumulation case

packages-user/data-base/src/map/mapLayer.test.ts

@@ -9,6 +9,7 @@ import {
     FaceGroup,
     FaceManager,
     RoleFaceBinder,
+    SaveCompression,
     TileStore,
     TileType
 } from '@user/data-common';
@@ -590,6 +591,30 @@ describe('MapLayer dynamic conversion', () => {
         expect(result.info.map(info => info.code)).toContain(130);
         await result.ret;
     });
+
+    // 验证 loadState 先清空既有动态块并触发删除钩子（#06-17-8 读档不累积）
+    it('clears existing dynamic tiles before loading', () => {
+        const { layer } = createFixture([0, 0, 0, 0]);
+        const deleted: IDynamicTile[] = [];
+        layer
+            .addHook({
+                onDeleteDynamic: async tile => {
+                    deleted.push(tile);
+                }
+            })
+            .load();
+        const first = layer.createDynamic(1, 0, 0);
+        const second = layer.createDynamic(1, 1, 0);
+        const saved = layer.saveState(SaveCompression.NoCompression);
+        const extra = layer.createDynamic(1, 0, 1);
+
+        layer.loadState(saved, SaveCompression.NoCompression);
+
+        expect([...layer.iterateDynamicTiles()]).toHaveLength(2);
+        expect([...layer.getDynamicTilesAt(0, 1)]).toHaveLength(0);
+        expect(deleted).toEqual([first, second, extra]);
+        expect([...layer.iterateDynamicTiles()]).not.toContain(first);
+    });
 });
 
 describe('MapLayer dirty state and doors', () => {

packages-user/data-base/src/map/mapLayer.ts

@@ -848,6 +848,19 @@ export class MapLayer
         }
     }
 
+    /**
+     * 清空本图层全部既有动态图块，使读档后的动态块与存档点一致
+     * 逐块复用删除语义，会触发 `onDeleteDynamic` 钩子，但读档为同步流程，不等待钩子完成
+     */
+    private clearDynamics(): void {
+        const tiles = [...this.iterateDynamicTiles()];
+        for (const tile of tiles) {
+            this.syncStaticEvent(tile, false);
+            this.removeTile(tile);
+            this.forEachHook(hook => hook.onDeleteDynamic?.(tile));
+        }
+    }
+
     /**
      * 以无压缩方式读取当前图层
      * @param save 图层存档
@@ -920,6 +933,7 @@ export class MapLayer
     }
 
     loadState(save: IMapLayerSave, compression: SaveCompression): void {
+        this.clearDynamics();
         if (compression === SaveCompression.HighCompression) {
             this.loadHighCompression(save);
         } else if (compression === SaveCompression.LowCompression) {

packages-user/data-base/src/map/saveLoad.test.ts

@@ -215,6 +215,24 @@ describe('MapLayer save and load round trips', () => {
         expect(lowResult.info.map(info => info.code)).toContain(124);
         expect(highResult.info.map(info => info.code)).toContain(124);
     });
+
+    // 验证动态块多于存档时读档后等于存档，且重复读档不累积（#06-17-8）
+    it('does not accumulate dynamic tiles when loading fewer than present', () => {
+        for (const compression of SAVE_COMPRESSIONS) {
+            const { layer } = createMapFixture();
+            setLayerReference(layer);
+            layer.createDynamic(1, 0, 0);
+            const saved = layer.saveState(compression);
+            layer.createDynamic(1, 1, 0);
+            layer.createDynamic(1, 1, 0);
+
+            layer.loadState(saved, compression);
+            expect([...layer.iterateDynamicTiles()]).toHaveLength(1);
+
+            layer.loadState(saved, compression);
+            expect([...layer.iterateDynamicTiles()]).toHaveLength(1);
+        }
+    });
 });
 
 describe('GameMap save and load round trips', () => {