News informational-only: gate sentiment bonus/penalty off by default

Add NewsConfig.sentiment_affects_signals (default False), gating the +5
aligned-sentiment confidence bonus and the 10-pt news_conflict penalty.
With event_risk_caps_signals already False, live decisions are now pure
technical, matching the backtester (use_news=False). Warnings and the
sentiment display are unchanged. Adds a gating regression test.

Claude-Session: https://claude.ai/code/session_01FMaaPdrrrQuh1VvGQH1icN

test_all.py

@@ -1240,6 +1240,38 @@ def _():
     assert PlatformConfig().news.event_risk_caps_signals is False
 
 
+@test("Sentiment signal gating obeys news.sentiment_affects_signals")
+def _():
+    config = PlatformConfig()
+    agg = SignalAggregator(config)
+    dfs = {
+        Timeframe.H1: make_ohlcv(300, seed=42),
+        Timeframe.M15: make_ohlcv(300, seed=43),
+        Timeframe.H4: make_ohlcv(300, seed=44),
+    }
+    report = agg.analyze_from_dataframes("XAU/USD", dfs, use_news=False)
+
+    def recompute(sentiment, affects):
+        config.news.sentiment_affects_signals = affects
+        report.news_sentiment = sentiment
+        report.warnings = []
+        agg._compute_final_signal(report)
+        return report.final_confidence
+
+    score_sign = 1 if report.primary_score >= 0 else -1
+    aligned, conflicting = 0.5 * score_sign, -0.5 * score_sign
+
+    baseline = recompute(0.0, False)
+    # default: neither aligned sentiment nor conflict moves confidence
+    assert recompute(aligned, False) == baseline, "aligned sentiment must not add confidence"
+    assert recompute(conflicting, False) == baseline, "conflicting sentiment must not penalize"
+    assert any("CONFLICTS" in w for w in report.warnings), "conflict warning must persist"
+    # flag on: aligned sentiment adds confidence again
+    assert recompute(aligned, True) > baseline, "flag on must restore the alignment bonus"
+    # PlatformConfig default is off (news is informational only)
+    assert PlatformConfig().news.sentiment_affects_signals is False
+
+
 @test("SignalAggregator._generate_trade_setup BUY direction")
 def _():
     config = PlatformConfig()