task-29: 合并 scope 状态查询与更新，减少单 chunk 数据库往返

persistResultScope 复用接收前已加载的 scope，不再重复 selectOne ——
每个分片接收的 scope 查询从 2 次降为 1 次；空分片校验前移至任何
scope 查询之前，非法分片零数据库往返。任务级分布式锁保证预读 scope
在锁内不过期。

backend-java/src/main/java/com/nanri/aiimage/modules/shopdatacrawl/service/ShopDataCrawlTaskService.java

@@ -1251,11 +1251,6 @@ public class ShopDataCrawlTaskService {
         int chunkTotal = incoming.getChunkTotal();
         validateChunkMetadata(chunkIndex, chunkTotal);
 
-        String scopeKey = resultChunkScopeKey(shopKey);
-        String scopeHash = DigestUtil.sha256Hex(scopeKey);
-        TaskScopeStateEntity scope = findResultScope(taskId, scopeHash);
-        validateChunkTotal(scope == null ? null : scope.getChunkTotal(), chunkTotal);
-
         List<ShopDataCrawlCountryResultDto> countryResults = copyCountryResults(incoming.getCountryResults());
         if (!hasProcessableChunkData(incoming.getCountryResults())) {
             throw new BusinessException("店铺数据抓取结果分片内容为空，拒绝接收");
@@ -1263,6 +1258,11 @@ public class ShopDataCrawlTaskService {
         String payloadJson = writeJson(countryResults, "序列化店铺数据抓取结果分片失败");
         String payloadHash = DigestUtil.sha256Hex(payloadJson);
 
+        String scopeKey = resultChunkScopeKey(shopKey);
+        String scopeHash = DigestUtil.sha256Hex(scopeKey);
+        TaskScopeStateEntity scope = findResultScope(taskId, scopeHash);
+        validateChunkTotal(scope == null ? null : scope.getChunkTotal(), chunkTotal);
+
         ensureRustfsPayloadStorageEnabled();
         String storedPayload = transientPayloadStorageService.storeChunkPayloadVersioned(
                 MODULE_TYPE, taskId, scopeHash, chunkIndex, payloadJson);
@@ -1300,7 +1300,7 @@ public class ShopDataCrawlTaskService {
         }
 
         try {
-            persistResultScope(taskId, scopeKey, scopeHash, chunkTotal, receivedChunkCount);
+            persistResultScope(scope, taskId, scopeKey, scopeHash, chunkTotal, receivedChunkCount);
         } catch (RuntimeException ex) {
             // 分片行与 scope 计数器是一致性单元：状态写入失败则回滚本次插入的分片行与 payload，
             // 客户端重试会走全新插入路径，计数器不会因重试重复计数或永久欠计。
@@ -1380,12 +1380,16 @@ public class ShopDataCrawlTaskService {
         return chunkTotal != null && chunkTotal > 0 ? Math.min(chunkTotal, count) : count;
     }
 
-    private void persistResultScope(Long taskId,
+    /**
+     * 复用接收前已加载的 scope（Task 29：合并查询与更新，单 chunk 的 scope 往返 2 次降为 1 次）。
+     * 任务级分布式锁串行化同一任务的接收，预读 scope 在锁内不会过期。
+     */
+    private void persistResultScope(TaskScopeStateEntity scope,
+                                    Long taskId,
                                     String scopeKey,
                                     String scopeHash,
                                     int chunkTotal,
                                     int receivedChunkCount) {
-        TaskScopeStateEntity scope = findResultScope(taskId, scopeHash);
         validateChunkTotal(scope == null ? null : scope.getChunkTotal(), chunkTotal);
         LocalDateTime now = LocalDateTime.now();
         if (scope == null) {