feat(通知模板): 支持 case 取值映射与事件名匹配渲染

Motivation:
让通知模板能够将 action、event 等原始枚举值映射为可读中文文案，并支持按事件名后缀匹配；同时简化 SafeW 消息发送格式，避免 Markdown 转义引入的显示问题。

Changes:

* 新增 `case` 模板函数，按值匹配 key/文案并支持末尾奇数参数作为默认值
* `case` 匹配兼容事件名后缀（如 trade.close 匹配 .close）
* `line` 前缀自动去除末尾冒号，避免重复冒号
* 模板渲染前自动注入 event 字段，便于模板按事件名取值
* SafeW 消息改为纯文本发送，移除 MarkdownV2 转义

internal/engine/renderer.go

@@ -16,7 +16,10 @@ func NewRenderer() *Renderer {
 func (r *Renderer) Render(tmplContent string, data map[string]interface{}) (string, error) {
 	tmpl, err := template.New("notify").
 		Option("missingkey=zero").
-		Funcs(template.FuncMap{"line": templateLine}).
+		Funcs(template.FuncMap{
+			"line": templateLine,
+			"case": templateCase,
+		}).
 		Parse(tmplContent)
 	if err != nil {
 		return "", fmt.Errorf("parse template: %w", err)
@@ -33,7 +36,41 @@ func templateLine(label string, v any) string {
 	if isEmptyValue(v) {
 		return ""
 	}
-	return label + "：" + fmt.Sprint(v) + "\n"
+	return strings.TrimRight(label, ":：") + "：" + fmt.Sprint(v) + "\n"
+}
+
+func templateCase(value any, pairs ...any) string {
+	got := stringify(value)
+	n := len(pairs)
+	def := got
+	if n%2 == 1 {
+		def = stringify(pairs[n-1])
+		pairs = pairs[:n-1]
+	}
+	for i := 0; i+1 < len(pairs); i += 2 {
+		if caseKeyMatch(got, stringify(pairs[i])) {
+			return stringify(pairs[i+1])
+		}
+	}
+	return def
+}
+
+func caseKeyMatch(value, key string) bool {
+	v := strings.ToLower(strings.TrimSpace(value))
+	k := strings.ToLower(strings.TrimSpace(key))
+	k = strings.TrimPrefix(k, ".")
+	vSeg := v
+	if i := strings.LastIndex(v, "."); i >= 0 {
+		vSeg = v[i+1:]
+	}
+	return k == v || k == strings.TrimPrefix(v, ".") || k == vSeg
+}
+
+func stringify(v any) string {
+	if v == nil {
+		return ""
+	}
+	return fmt.Sprint(v)
 }
 
 func isEmptyValue(v any) bool {

internal/engine/renderer_test.go

@@ -46,6 +46,16 @@ func TestRendererLineOmitsEmpty(t *testing.T) {
 	}
 }
 
+func TestRendererLineLabelAlreadyHasColon(t *testing.T) {
+	r := NewRenderer()
+	out, err := r.Render(`{{line "平均价：" .totalAvgPx}}`, map[string]interface{}{"totalAvgPx": 1029})
+	if err != nil {
+		t.Fatal(err)
+	}
+	if strings.Count(out, "：") != 1 || !strings.Contains(out, "平均价：1029") {
+		t.Fatalf("out=%q", out)
+	}
+}
 func TestRendererLineMissingKey(t *testing.T) {
 	r := NewRenderer()
 	out, err := r.Render(`{{line "平均价" .totalAvgPx}}{{line "币种" .symbol}}`, map[string]interface{}{"symbol": "ICP"})
@@ -56,3 +66,45 @@ func TestRendererLineMissingKey(t *testing.T) {
 		t.Fatalf("out=%q", out)
 	}
 }
+
+func TestRendererCaseSwitch(t *testing.T) {
+	r := NewRenderer()
+	tmpl := `{{case .action "OPEN" "开仓" "CLOSE" "平仓" "GAIN" "止盈"}}`
+	out, err := r.Render(tmpl, map[string]interface{}{"action": "CLOSE"})
+	if err != nil {
+		t.Fatal(err)
+	}
+	if out != "平仓" {
+		t.Fatalf("action CLOSE: %q", out)
+	}
+	out, err = r.Render(tmpl, map[string]interface{}{"action": "open"})
+	if err != nil {
+		t.Fatal(err)
+	}
+	if out != "开仓" {
+		t.Fatalf("action open: %q", out)
+	}
+}
+
+func TestRendererCaseEventSuffix(t *testing.T) {
+	r := NewRenderer()
+	tmpl := `{{case .event ".open" "开仓" ".close" "平仓"}}`
+	out, err := r.Render(tmpl, map[string]interface{}{"event": "trade.close"})
+	if err != nil {
+		t.Fatal(err)
+	}
+	if out != "平仓" {
+		t.Fatalf("event trade.close: %q", out)
+	}
+}
+
+func TestRendererCaseDefault(t *testing.T) {
+	r := NewRenderer()
+	out, err := r.Render(`{{case .action "OPEN" "开仓" "未知"}}`, map[string]interface{}{"action": "HOLD"})
+	if err != nil {
+		t.Fatal(err)
+	}
+	if out != "未知" {
+		t.Fatalf("got %q", out)
+	}
+}