scheduler: auto-detect new signals once per day, deduplicate existing

- scheduler tick runs detect after fetch+score (once per UTC day)
- ChanSignalDetector skips already-recorded signals
- Prevents duplicate signal_features entries on repeated runs

ChanMacro/scheduler.py

@@ -115,7 +115,23 @@ class MacroScheduler:
             conn.commit()
             conn.close()
 
-            self._last_run = datetime.now(timezone.utc)
+            # 检测新信号（每天运行一次，UTC 0 点后首次触发）
+            now = datetime.now(timezone.utc)
+            if self._last_run is None or now.date() > self._last_run.date():
+                try:
+                    from chan_integration import ChanSignalDetector
+                    detector = ChanSignalDetector()
+                    # 检测最近 90 天的 4h 信号
+                    count = detector.populate_signal_features(
+                        start_date=(today - __import__('datetime').timedelta(days=90)).isoformat(),
+                        end_date=today.isoformat(),
+                    )
+                    if count > 0:
+                        logger.info(f"新增 {count} 条信号记录")
+                except Exception as e:
+                    logger.debug(f"信号检测跳过: {e}")
+
+            self._last_run = now
             logger.info(
                 f"Tick 完成: regime={r.regime.value} conf={r.confidence:.2f} "
                 f"breadth={br.score:.0f}({br.breadth_bucket.value}) "