task-50: 结果明细批量 upsert 写入器与唯一键幂等

CollectDataResultItemBatchWriter 按唯一键 uk_task_scope_item 批量 upsert
biz_task_result_item：一次批量查询现有行（payload_hash 相等即跳过），
分批发 INSERT ... ON DUPLICATE KEY UPDATE，替代逐行 select/insert/update；
旧格式逐行 payload 升级为引用时物理删除（引用计数兜底）。CollectDataService
submitResult 接入批量写入，移除逐行 upsertResultItem。

backend-java/src/main/resources/application.yml

@@ -264,6 +264,7 @@ aiimage:
     brand-check-batch-size: ${AIIMAGE_COLLECT_DATA_BRAND_CHECK_BATCH_SIZE:10}
     brand-check-cache-capacity: ${AIIMAGE_COLLECT_DATA_BRAND_CHECK_CACHE_CAPACITY:512}
     invalid-asin-batch-size: ${AIIMAGE_COLLECT_DATA_INVALID_ASIN_BATCH_SIZE:100}
+    result-item-batch-size: ${AIIMAGE_COLLECT_DATA_RESULT_ITEM_BATCH_SIZE:100}
   image-video:
     coze-base-url: ${AIIMAGE_IMAGE_VIDEO_COZE_BASE_URL:https://api.coze.cn}
     coze-token: ${AIIMAGE_IMAGE_VIDEO_COZE_TOKEN:sat_Ws4VB1caOPasDivpKIvtOySYx3lhKgQ95H3crIh0tBwiNYtPTyi6bqe0pBaRzpVu}