fix(消息去重): 去重键加入来源维度，避免跨来源信号被误去重

Motivation:
不同来源（如 crypto-strategy 与 trade-signal）可能产生策略、币种、周期、方向、价格完全一致的信号，旧去重键仅按这五维计算，导致后到的不同来源信号被误判为重复而漏推，无法支撑跟单策略等新增来源并行推送。

Changes:

* 信号去重键新增来源（source）维度，不同来源的相同信号不再互相去重
* 信号哈希计算时透传来源名称，同一来源内的重复消息仍正常去重
* 补充跟单策略文案模板的渲染测试与接口创建文档

internal/subscriber/dedup_test.go

@@ -26,7 +26,7 @@ func TestMessageHashStable(t *testing.T) {
 }
 
 func TestSignalHashIgnoresUnrelatedFields(t *testing.T) {
-	a := SignalHash(map[string]interface{}{
+	a := SignalHash("crypto-strategy", map[string]interface{}{
 		"strategyCode": "ai-crypto-signals",
 		"symbol":       "CRV",
 		"period":       "1h",
@@ -34,7 +34,7 @@ func TestSignalHashIgnoresUnrelatedFields(t *testing.T) {
 		"price":        0.2528,
 		"eventTime":    int64(1),
 	})
-	b := SignalHash(map[string]interface{}{
+	b := SignalHash("crypto-strategy", map[string]interface{}{
 		"strategyCode": "ai-crypto-signals",
 		"currency":     "CRV",
 		"period":       "1h",
@@ -45,7 +45,7 @@ func TestSignalHashIgnoresUnrelatedFields(t *testing.T) {
 	if a == "" || a != b {
 		t.Fatalf("same signal fields should hash equal, a=%q b=%q", a, b)
 	}
-	c := SignalHash(map[string]interface{}{
+	c := SignalHash("crypto-strategy", map[string]interface{}{
 		"strategyCode": "ai-crypto-signals",
 		"symbol":       "CRV",
 		"period":       "1h",
@@ -55,6 +55,16 @@ func TestSignalHashIgnoresUnrelatedFields(t *testing.T) {
 	if a == c {
 		t.Fatal("different price should hash differently")
 	}
+	otherSrc := SignalHash("trade-signal", map[string]interface{}{
+		"strategyCode": "ai-crypto-signals",
+		"symbol":       "CRV",
+		"period":       "1h",
+		"direction":    "LONG",
+		"price":        0.2528,
+	})
+	if a == otherSrc {
+		t.Fatal("different sources should hash differently")
+	}
 }
 
 func TestMemoryDeduperClaimOnce(t *testing.T) {
@@ -121,6 +131,37 @@ func TestHandleDedupByStrategySymbolPeriodDirectionPrice(t *testing.T) {
 	}
 }
 
+func TestHandleDedupKeepsDifferentSources(t *testing.T) {
+	dedup := NewMemoryDeduper()
+	var n atomic.Int32
+	process := func(context.Context, notify.Request) (notify.Result, error) {
+		n.Add(1)
+		return notify.Result{Matched: true}, nil
+	}
+	lookup := func(_ context.Context, name string) (*model.Source, error) {
+		return &model.Source{ID: 1, Name: name, Status: 1}, nil
+	}
+	conv := cryptostrategy.NewConverter()
+	body := []byte(`{
+		"eventType":"SIGNAL_RECEIVED","symbol":"CRV","direction":"LONG",
+		"payload":"{\"strategyCode\":\"ai-crypto-signals\",\"period\":\"1h\",\"currency\":\"CRV\",\"isClose\":true,\"isGain\":true,\"price\":0.2528}",
+		"eventTime":1786899538978
+	}`)
+	if d := HandleMessage(context.Background(), HandleInput{
+		Body: body, SourceName: "crypto-strategy", MaxRetry: 3, Deduper: dedup,
+	}, conv, lookup, process); d != DispositionAck {
+		t.Fatalf("first=%v", d)
+	}
+	if d := HandleMessage(context.Background(), HandleInput{
+		Body: body, SourceName: "trade-signal", MaxRetry: 3, Deduper: dedup,
+	}, conv, lookup, process); d != DispositionAck {
+		t.Fatalf("other source=%v", d)
+	}
+	if n.Load() != 2 {
+		t.Fatalf("different sources should both process, got %d", n.Load())
+	}
+}
+
 func TestHandleDuplicateAckSkipsProcess(t *testing.T) {
 	dedup := NewMemoryDeduper()
 	var n atomic.Int32