Fix weekend filter: use precise forex market hours (Fri 22:00–Sun 22:00 UTC)

The old `weekday() >= 5` check blocked all of Sunday, but the forex
market reopens Sunday 22:00 UTC (Sydney open). Now uses proper time-based
check so the bot fetches data and generates signals on Sunday evening.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

signal_aggregator.py

@@ -21,6 +21,19 @@ from news_engine import NewsEngine, FundamentalContext
 logger = logging.getLogger(__name__)
 
 
+def _is_forex_weekend(now_utc: datetime) -> bool:
+    """Forex market closed: Friday 22:00 UTC → Sunday 22:00 UTC (Sydney open)."""
+    wd = now_utc.weekday()
+    hour = now_utc.hour
+    if wd == 4 and hour >= 22:  # Friday after 22:00
+        return True
+    if wd == 5:  # All Saturday
+        return True
+    if wd == 6 and hour < 22:  # Sunday before 22:00
+        return True
+    return False
+
+
 @dataclass
 class TradeSetup:
     pair: str
@@ -108,7 +121,7 @@ class SignalAggregator:
         if pair_info["display"] == "XAU/USD" and self.config.xau_strategy.enabled:
             xau_cfg = self.config.xau_strategy
 
-            if xau_cfg.weekend_filter and now_utc.weekday() >= 5:
+            if xau_cfg.weekend_filter and _is_forex_weekend(now_utc):
                 report = SignalReport(
                     symbol=symbol,
                     display_name=pair_info["display"],
@@ -122,7 +135,7 @@ class SignalAggregator:
                 return report
 
             if xau_cfg.allowed_weekdays and now_utc.weekday() not in xau_cfg.allowed_weekdays:
-                day_names = {0: "Mon", 1: "Tue", 2: "Wed", 3: "Thu", 4: "Fri"}
+                day_names = {0: "Mon", 1: "Tue", 2: "Wed", 3: "Thu", 4: "Fri", 5: "Sat", 6: "Sun"}
                 allowed = "/".join(day_names.get(d, str(d)) for d in xau_cfg.allowed_weekdays)
                 report = SignalReport(
                     symbol=symbol,