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/models/__init__.py

@@ -2,7 +2,7 @@ from alphapulse.core.db import Base
 from alphapulse.models.ai import AiProvider, ChatMessage, ChatSession, ContextVersion, SkillNode, SkillVersion
 from alphapulse.models.market import Kline, KlineSyncState, MarketSymbol
 from alphapulse.models.news import CrawlLog, CrawlRun, NewsItem, NewsRevision, RawBody, RawResponse, Source
-from alphapulse.models.trading import TradingAccount, TradingAnalysis, TradingEvent, TradingFill, TradingOrder, TradingSymbol
+from alphapulse.models.trading import NewsSignal, TradingAccount, TradingAnalysis, TradingEvent, TradingFill, TradingOrder, TradingSymbol
 
 __all__ = [
     "AiProvider",
@@ -16,6 +16,7 @@ __all__ = [
     "KlineSyncState",
     "MarketSymbol",
     "NewsItem",
+    "NewsSignal",
     "NewsRevision",
     "RawBody",
     "RawResponse",