refactor: 提取分页魔法数字为 pagination 常量

- handler 层: device/log/webhook/user handler 使用 pagination.DefaultPageSize/MaxPageSize
- service 层: device/login_log/operation_log service 使用 pagination.DefaultPageSize
- repository 层: user repository 使用 pagination.DefaultPageSize/MaxPageSize
- 消除 8 处硬编码的 20/100 分页魔法数字

internal/api/handler/device_handler.go

@@ -10,6 +10,7 @@ import (
 
 	"github.com/user-management-system/internal/api/middleware"
 	"github.com/user-management-system/internal/domain"
+	"github.com/user-management-system/internal/pagination"
 	"github.com/user-management-system/internal/service"
 )
 
@@ -88,9 +89,9 @@ func (h *DeviceHandler) GetMyDevices(c *gin.Context) {
 	}
 
 	page, _ := strconv.Atoi(c.DefaultQuery("page", "1"))
-	pageSize, _ := strconv.Atoi(c.DefaultQuery("page_size", "20"))
-	if pageSize < 1 || pageSize > 100 {
-		pageSize = 20
+	pageSize, _ := strconv.Atoi(c.DefaultQuery("page_size", strconv.Itoa(pagination.DefaultPageSize)))
+	if pageSize < 1 || pageSize > pagination.MaxPageSize {
+		pageSize = pagination.DefaultPageSize
 	}
 
 	devices, total, err := h.deviceService.GetUserDevices(c.Request.Context(), userID, page, pageSize)
@@ -316,9 +317,9 @@ func (h *DeviceHandler) GetUserDevices(c *gin.Context) {
 	}
 
 	page, _ := strconv.Atoi(c.DefaultQuery("page", "1"))
-	pageSize, _ := strconv.Atoi(c.DefaultQuery("page_size", "20"))
-	if pageSize < 1 || pageSize > 100 {
-		pageSize = 20
+	pageSize, _ := strconv.Atoi(c.DefaultQuery("page_size", strconv.Itoa(pagination.DefaultPageSize)))
+	if pageSize < 1 || pageSize > pagination.MaxPageSize {
+		pageSize = pagination.DefaultPageSize
 	}
 
 	devices, total, err := h.deviceService.GetUserDevices(c.Request.Context(), userID, page, pageSize)