fix: calculate total file size on backend instead of frontend

- Backend returns total_size for all matching versions
- Frontend uses backend's total_size instead of computing from current page

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

backend/internal/router/admin/versions.go

@@ -98,6 +98,27 @@ func handleGetAllVersions(c *gin.Context) {
 	var forcedCount int64
 	database.DB.Model(&model.Version{}).Where("application_id IN ? AND update_strategy = ?", appIDs, "forced").Count(&forcedCount)
 
+	// 计算总文件大小
+	var totalSize int64
+	sizeQuery := database.DB.Model(&model.Version{}).Where("application_id IN ?", appIDs)
+	if applicationIDFilter != "" {
+		sizeQuery = sizeQuery.Where("application_id = ?", applicationIDFilter)
+	}
+	if updateStrategyFilter != "" {
+		sizeQuery = sizeQuery.Where("update_strategy = ?", updateStrategyFilter)
+	}
+	if updateTypeFilter != "" {
+		sizeQuery = sizeQuery.Where("update_type = ?", updateTypeFilter)
+	}
+	if updateMethodFilter != "" {
+		sizeQuery = sizeQuery.Where("update_method = ?", updateMethodFilter)
+	}
+	if searchFilter != "" {
+		searchLower := strings.ToLower(searchFilter)
+		sizeQuery = sizeQuery.Where("LOWER(version) LIKE ? OR LOWER(description) LIKE ?", "%"+searchLower+"%", "%"+searchLower+"%")
+	}
+	sizeQuery.Select("COALESCE(SUM(file_size), 0)").Scan(&totalSize)
+
 	query := database.DB.Where("application_id IN ?", appIDs)
 	if applicationIDFilter != "" {
 		query = query.Where("application_id = ?", applicationIDFilter)
@@ -190,6 +211,7 @@ func handleGetAllVersions(c *gin.Context) {
 		"versions":     result,
 		"total":        total,
 		"forced_count": forcedCount,
+		"total_size":   totalSize,
 	})
 }