feat: 算力引擎 Go 后端核心（new-api）

- 统一 OpenAI 兼容 /v1 中继 + 渠道/额度/令牌/流水
- 各领域包：relay 模型网关、model 数据层、controller 管理 API

relaykit/relayconvert/kitutil/value.go

@@ -0,0 +1,52 @@
+package kitutil
+
+import (
+	"fmt"
+	"strconv"
+	"strings"
+	"time"
+
+	"github.com/google/uuid"
+)
+
+func GetPointer[T any](v T) *T {
+	return &v
+}
+
+func Interface2String(inter interface{}) string {
+	switch inter.(type) {
+	case string:
+		return inter.(string)
+	case int:
+		return fmt.Sprintf("%d", inter.(int))
+	case float64:
+		return strconv.FormatFloat(inter.(float64), 'f', -1, 64)
+	case bool:
+		if inter.(bool) {
+			return "true"
+		} else {
+			return "false"
+		}
+	case nil:
+		return ""
+	}
+	return fmt.Sprintf("%v", inter)
+}
+
+func String2Int(str string) int {
+	num, err := strconv.Atoi(str)
+	if err != nil {
+		return 0
+	}
+	return num
+}
+
+func GetUUID() string {
+	code := uuid.New().String()
+	code = strings.Replace(code, "-", "", -1)
+	return code
+}
+
+func GetTimestamp() int64 {
+	return time.Now().Unix()
+}