Support isolated deployment without duplicate background synchronization

backend/.env.example

@@ -260,3 +260,6 @@ PLANNING_RANK_BOARD_SNAPSHOT_LOG_TABLE=planning_rank_board_snapshot_sync_log
 PLANNING_RANK_BOARD_SNAPSHOT_LOCK_KEY=planning_rank_board_snapshot_daily
 PLANNING_RANK_BOARD_SNAPSHOT_CRON=0 0 * * *
 PLANNING_RANK_BOARD_SNAPSHOT_TIMEZONE=Asia/Shanghai
+
+# 多实例部署时可禁用此实例的后台任务，避免重复同步共享业务库
+ENABLE_BACKGROUND_JOBS=true

backend/src/index.js

@@ -716,6 +716,11 @@ async function startServer(options = {}) {
   console.log(`   [缓存] ${redisTest.message}`);
   console.log('='.repeat(50));
 
+  if (String(process.env.ENABLE_BACKGROUND_JOBS || 'true').toLowerCase() === 'false') {
+    console.log('⏸️ 后台定时任务和预热已关闭，业务请求按需处理');
+    return;
+  }
+
   startScheduler();
   startStockSelectionSchedulers();
   startTaobaoProductEmbeddingSchedulers();