feat(apple): 添加通过transaction_id附加苹果交易功能

新增通过transaction_id附加苹果交易的功能，包括：
1. 添加AttachAppleTransactionByIdRequest类型和对应路由
2. 实现AppleIAPConfig配置模型
3. 添加ServerAPI获取交易信息的实现
4. 优化JWS解析逻辑，增加cleanB64函数处理空格
5. 完善苹果通知处理逻辑的日志和注释

internal/handler/notify/appleIAPNotifyHandler.go

@@ -1,9 +1,10 @@
 package notify
 
 import (
-	"github.com/gin-gonic/gin"
-	"io"
 	"encoding/json"
+	"io"
+
+	"github.com/gin-gonic/gin"
 	"github.com/perfect-panel/server/internal/logic/notify"
 	"github.com/perfect-panel/server/internal/svc"
 	"github.com/perfect-panel/server/pkg/result"