feat: 趋势过滤信号记录系统 + 实时涨跌方向判断

- 新增 TrendFilter 信号记录（enter/exit），按完整信号和高分信号两档分类
- 信号持久化到 data/trend_signals_cache.json，开机自动恢复
- 新增 /api/trend-signals API + SSE trend_signal 实时广播
- 前端新增完整信号卡片和高分信号卡片，移除旧趋势检测卡片
- 评分加入 1h 涨跌方向和实时 drift 惩罚，下跌币不触发信号
- OKX 交易所支持（累积变动、动量、趋势检测）
- 修复 trend_filter.go 编译错误

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

momentum.go

@@ -18,6 +18,7 @@ var momentumWindows = []momentumWindow{
 	{"t1s", 20, "1s"},
 	{"t5s", 100, "5s"},
 	{"t15s", 300, "15s"},
+	{"t60s", 1200, "60s"},
 }
 
 const maxMomentumRecords = 600
@@ -35,15 +36,19 @@ type MomentumEntry struct {
 	BG1s      float64 `json:"bg_1s"`
 	BG5s      float64 `json:"bg_5s"`
 	BG15s     float64 `json:"bg_15s"`
+	BG60s     float64 `json:"bg_60s"`
 	HL1s      float64 `json:"hl_1s"`
 	HL5s      float64 `json:"hl_5s"`
 	HL15s     float64 `json:"hl_15s"`
+	HL60s     float64 `json:"hl_60s"`
 	BN1s      float64 `json:"bn_1s"`
 	BN5s      float64 `json:"bn_5s"`
 	BN15s     float64 `json:"bn_15s"`
+	BN60s     float64 `json:"bn_60s"`
 	OKX1s     float64 `json:"okx_1s"`
 	OKX5s     float64 `json:"okx_5s"`
 	OKX15s    float64 `json:"okx_15s"`
+	OKX60s    float64 `json:"okx_60s"`
 	Score     float64 `json:"score"`     // max abs change across all windows
 	Direction string  `json:"direction"` // "up", "down", "flat", "mixed"
 }
@@ -105,6 +110,7 @@ func (mt *MomentumTracker) Snapshot(thresholdPct float64) []MomentumEntry {
 			entry.BG1s = changes[0]
 			entry.BG5s = changes[1]
 			entry.BG15s = changes[2]
+			entry.BG60s = changes[3]
 			allChanges = append(allChanges, changes[:]...)
 		}
 		if hasHL {
@@ -112,6 +118,7 @@ func (mt *MomentumTracker) Snapshot(thresholdPct float64) []MomentumEntry {
 			entry.HL1s = changes[0]
 			entry.HL5s = changes[1]
 			entry.HL15s = changes[2]
+			entry.HL60s = changes[3]
 			allChanges = append(allChanges, changes[:]...)
 		}
 		if hasBN {
@@ -119,6 +126,7 @@ func (mt *MomentumTracker) Snapshot(thresholdPct float64) []MomentumEntry {
 			entry.BN1s = changes[0]
 			entry.BN5s = changes[1]
 			entry.BN15s = changes[2]
+			entry.BN60s = changes[3]
 			allChanges = append(allChanges, changes[:]...)
 		}
 		if hasOK {
@@ -126,6 +134,7 @@ func (mt *MomentumTracker) Snapshot(thresholdPct float64) []MomentumEntry {
 			entry.OKX1s = changes[0]
 			entry.OKX5s = changes[1]
 			entry.OKX15s = changes[2]
+			entry.OKX60s = changes[3]
 			allChanges = append(allChanges, changes[:]...)
 		}
 
@@ -178,10 +187,10 @@ func (mt *MomentumTracker) Snapshot(thresholdPct float64) []MomentumEntry {
 	return result
 }
 
-// calcWindows computes change% for all 3 windows: (current - old) / old * 100.
+// calcWindows computes change% for all windows: (current - old) / old * 100.
 // Returns 0 for windows that don't have enough data yet.
-func calcWindows(buf *momentumBuffer) [3]float64 {
-	var result [3]float64
+func calcWindows(buf *momentumBuffer) [4]float64 {
+	var result [4]float64
 	for i, w := range momentumWindows {
 		if buf.count < w.Ticks+1 {
 			continue