refactor(api): streamline API requests with requestJson and requestBlob functions

Replaced direct fetch calls with requestJson and requestBlob utility functions across multiple components for improved consistency and error handling. This change enhances the maintainability of the codebase by centralizing API request logic and ensuring uniform handling of authentication and response parsing.

app/(main)/backups/page.tsx

@@ -28,6 +28,7 @@ import { useDataSource } from "@/lib/data-source"
 import { listServers } from "@/shared/api/servers"
 import { toFrontendServer } from "@/entities/server/model/mappers"
 import { createBackupsAsync, deleteBackup, getBackupJob, getBackupScheduleSettings, listBackups, putBackupScheduleSettings, type BackupItem } from "@/shared/api/backups"
+import { requestBlob } from "@/shared/api/http-client"
 import { toast } from "sonner"
 import {
   Stepper,
@@ -276,8 +277,7 @@ export default function BackupsPage() {
   }
 
   async function handleDownload(id: string, fallbackFilename: string) {
-    const res = await fetch(`${backendUrl.replace(/\/$/, "")}/api/backups/${id}/download`)
-    if (!res.ok) throw new Error("Не удалось скачать файл")
+    const res = await requestBlob(backendUrl, `/api/backups/${id}/download`)
     const blob = await res.blob()
     const url = URL.createObjectURL(blob)
     const a = document.createElement("a")