Gate all XAU-only aggregator logic by pair

The SELL quality gate (6e), SELL volatility gate (6g), M5 noise gates
(6h), ATR trade-setup generator, and M5 pullback archetype are all
gold-tuned but previously keyed only on xau_strategy.enabled or the
timeframe, so they would have silently applied gold constants to any
other pair. Each now also requires display_name == "XAU/USD".

No behavior change for XAU (conditions are tautologically true for the
only registered pair today) — verified by test suite and pinned-window
backtest CSV diff.

signal_aggregator.py

@@ -704,6 +704,7 @@ class SignalAggregator:
             or (report.final_signal == SignalStrength.NEUTRAL and report.final_score < 0)
         )
         if (self.config.xau_strategy.enabled
+                and report.display_name == "XAU/USD"
                 and xau_is_sell_dir
                 and report.signal_quality not in self.config.xau_strategy.sell_min_quality):
             report.warnings.append(
@@ -734,6 +735,7 @@ class SignalAggregator:
         # Shorts in quiet markets fade against gold's macro uptrend;
         # only take sells when volatility regime confirms real selling.
         if (self.config.xau_strategy.enabled
+                and report.display_name == "XAU/USD"
                 and xau_is_sell_dir
                 and report.signal_quality in ("A+", "A", "B", "C")
                 and report.volatility_regime
@@ -744,12 +746,16 @@ class SignalAggregator:
             report.signal_quality = "D"
             report.trade_setup = None
 
-        # ── 6h. M5 noise gate ────────────────────────────────────
+        # ── 6h. M5 noise gate (gold-tuned thresholds — XAU only) ──
-        if self.config.primary_timeframe == Timeframe.M5:
+        if (self.config.primary_timeframe == Timeframe.M5
+                and report.display_name == "XAU/USD"):
             self._apply_m5_filters(report)
 
         # ── 7. Trade setup for actionable signals ──────────────────
-        if report.trade_setup is None and report.signal_quality in ("A+", "A"):
+        # ATR generator is XAU-only: it hardcodes gold pip value and
+        # 2-decimal price rounding.
+        if (report.trade_setup is None and report.signal_quality in ("A+", "A")
+                and report.display_name == "XAU/USD"):
             atr = (report.primary_analysis.key_levels.get("atr", 0)
                    if report.primary_analysis else 0)
             if atr > 0:
@@ -765,6 +771,7 @@ class SignalAggregator:
         # trend-continuation pullback (retrace to EMA21/KC-mid). Runs
         # after reasons so its marker lands at reasons[0] for tagging.
         if (self.config.primary_timeframe == Timeframe.M5
+                and report.display_name == "XAU/USD"
                 and self.config.xau_strategy.m5_pullback_enabled
                 and report.trade_setup is None
                 and report.signal_quality != "F"):