feat: 重构为三所价差异动监控系统

删除 HyperLiquid + 全部交易功能，构建自适应 surge 检测器。
- 新增 surge_detector.go: 每币独立滚动窗口基线，检测三所价差异常飙升
- 新增 SpreadCard/SurgeCard 前端组件
- 保留 momentum/trend/cumulative/trend_filter 扫描功能
- 更新文档和配置以反映新系统

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

trend_filter.go

@@ -484,21 +484,6 @@ func (tf *TrendFilter) computeFilterState(coin string, k1h, k5m []klineData, now
 	return fs
 }
 
-// median returns the median value of a sorted copy of the slice.
-func median(values []float64) float64 {
-	if len(values) == 0 {
-		return 0
-	}
-	sorted := make([]float64, len(values))
-	copy(sorted, values)
-	sort.Float64s(sorted)
-	mid := len(sorted) / 2
-	if len(sorted)%2 == 0 {
-		return (sorted[mid-1] + sorted[mid]) / 2
-	}
-	return sorted[mid]
-}
-
 // computeSignalScore calculates the composite signal score (0-100) from a FilterState.
 // Must be called after FreshAnomaly, PriceAboveEMA, and volume fields are set.
 func computeSignalScore(fs *FilterState) float64 {