fix: IAP 支付流程优化与关键 bug 修复

- getStatusLogic 类型断言修复（*user.User）
- restoreLogic 事务拆分为单条处理 + appAccountToken 解析
- attachTransactionLogic 提取 ParseProductIdDuration 共享函数
- 新增 config_helper.go 统一 Apple API 配置加载
- reconcileLogic 补充 BundleID 配置读取
- activateOrderLogic 邀请赠送天数逻辑完善

Co-Authored-By: claude-flow <ruv@ruv.net>

pkg/iap/apple/productmap.go

@@ -2,6 +2,8 @@ package apple
 
 import (
 	"encoding/json"
+	"strconv"
+	"strings"
 	"time"
 )
 
@@ -37,3 +39,44 @@ func CalcExpire(start time.Time, days int64) time.Time {
 	}
 	return start.Add(time.Duration(days) * 24 * time.Hour)
 }
+
+// ParsedProduct holds the result of parsing an Apple product ID.
+type ParsedProduct struct {
+	Unit     string // "Day", "Month", "Year"
+	Quantity int64
+}
+
+// ParseProductIdDuration extracts time unit and quantity from Apple product IDs.
+// e.g. "com.app.vip.day30" -> {Unit: "Day", Quantity: 30}
+func ParseProductIdDuration(productId string) *ParsedProduct {
+	pid := strings.ToLower(productId)
+	parts := strings.Split(pid, ".")
+	for i := len(parts) - 1; i >= 0; i-- {
+		p := parts[i]
+		var unit string
+		switch {
+		case strings.HasPrefix(p, "day"):
+			unit = "Day"
+			p = p[len("day"):]
+		case strings.HasPrefix(p, "month"):
+			unit = "Month"
+			p = p[len("month"):]
+		case strings.HasPrefix(p, "year"):
+			unit = "Year"
+			p = p[len("year"):]
+		default:
+			continue
+		}
+		digits := p
+		for j := 0; j < len(digits); j++ {
+			if digits[j] < '0' || digits[j] > '9' {
+				digits = digits[:j]
+				break
+			}
+		}
+		if q, e := strconv.ParseInt(digits, 10, 64); e == nil && q > 0 {
+			return &ParsedProduct{Unit: unit, Quantity: q}
+		}
+	}
+	return nil
+}