Record news signals forward for a no-trade edge test

The trader labels crypto news published after 2026-10-16 15:00 with
the configured model (category and BTC direction) and, four hours
later, backfills BTC/ETH 1m opens at publish, +5m, +1h and +4h from
the klines table. A drawer on the trading page shows the cumulative
returns of trading the labelled direction, after fees. Nothing is
traded; this only collects an out-of-sample record.

backend/src/alphapulse/trading/engine.py

@@ -1,4 +1,4 @@
-"""模拟盘交易进程：同步账户快照、执行器对账、调度分析。
+"""模拟盘交易进程：同步账户快照、执行器对账、调度分析、记录新闻信号。
 
 用法：python -m alphapulse.trading.engine
 """
@@ -13,6 +13,7 @@ from alphapulse.core.db import SessionLocal
 from alphapulse.models import TradingAnalysis, TradingSymbol
 from alphapulse.trading.analyst import run_analysis
 from alphapulse.trading.executor import executor_loop
+from alphapulse.trading.news_signals import news_signal_loop
 from alphapulse.trading.schedule import routine_requests
 from alphapulse.trading.snapshot import snapshot_loop
 
@@ -74,6 +75,7 @@ async def main() -> None:
         tg.create_task(snapshot_loop())
         tg.create_task(executor_loop())
         tg.create_task(analysis_loop())
+        tg.create_task(news_signal_loop())
 
 
 if __name__ == "__main__":