feat(backups): Add backup import API and improve backup download/import flow in UI

ts/classes/httpserver.ts

@@ -347,6 +347,8 @@ export class OneboxHttpServer {
       return await this.handleDeleteBackupRequest(backupId);
     } else if (path === '/api/backups/restore' && method === 'POST') {
       return await this.handleRestoreBackupRequest(req);
+    } else if (path === '/api/backups/import' && method === 'POST') {
+      return await this.handleImportBackupRequest(req);
     } else if (path === '/api/settings/backup-password' && method === 'POST') {
       return await this.handleSetBackupPasswordRequest(req);
     } else if (path === '/api/settings/backup-password' && method === 'GET') {
@@ -2278,6 +2280,118 @@ export class OneboxHttpServer {
     }
   }
 
+  /**
+   * Import a backup from file upload or URL
+   */
+  private async handleImportBackupRequest(req: Request): Promise<Response> {
+    try {
+      const contentType = req.headers.get('content-type') || '';
+      let filePath: string | null = null;
+      let newServiceName: string | undefined;
+      let tempFile = false;
+
+      if (contentType.includes('multipart/form-data')) {
+        // Handle file upload
+        const formData = await req.formData();
+        const file = formData.get('file');
+        newServiceName = formData.get('newServiceName')?.toString() || undefined;
+
+        if (!file || !(file instanceof File)) {
+          return this.jsonResponse({
+            success: false,
+            error: 'No file provided',
+          }, 400);
+        }
+
+        // Validate file extension
+        if (!file.name.endsWith('.tar.enc')) {
+          return this.jsonResponse({
+            success: false,
+            error: 'Invalid file format. Expected .tar.enc file',
+          }, 400);
+        }
+
+        // Save to temp location
+        const tempDir = './.nogit/temp-imports';
+        await Deno.mkdir(tempDir, { recursive: true });
+        filePath = `${tempDir}/${Date.now()}-${file.name}`;
+        tempFile = true;
+
+        const arrayBuffer = await file.arrayBuffer();
+        await Deno.writeFile(filePath, new Uint8Array(arrayBuffer));
+
+        logger.info(`Saved uploaded backup to ${filePath}`);
+      } else {
+        // Handle JSON body with URL
+        const body = await req.json();
+        const { url, newServiceName: serviceName } = body;
+        newServiceName = serviceName;
+
+        if (!url) {
+          return this.jsonResponse({
+            success: false,
+            error: 'URL is required when not uploading a file',
+          }, 400);
+        }
+
+        // Download from URL
+        const tempDir = './.nogit/temp-imports';
+        await Deno.mkdir(tempDir, { recursive: true });
+
+        const urlFilename = url.split('/').pop() || 'backup.tar.enc';
+        filePath = `${tempDir}/${Date.now()}-${urlFilename}`;
+        tempFile = true;
+
+        logger.info(`Downloading backup from ${url}...`);
+        const response = await fetch(url);
+        if (!response.ok) {
+          return this.jsonResponse({
+            success: false,
+            error: `Failed to download from URL: ${response.statusText}`,
+          }, 400);
+        }
+
+        const arrayBuffer = await response.arrayBuffer();
+        await Deno.writeFile(filePath, new Uint8Array(arrayBuffer));
+
+        logger.info(`Downloaded backup to ${filePath}`);
+      }
+
+      // Import using restoreBackup with mode='import'
+      const result = await this.oneboxRef.backupManager.restoreBackup(filePath, {
+        mode: 'import',
+        newServiceName,
+        overwriteExisting: false,
+        skipPlatformData: false,
+      });
+
+      // Clean up temp file
+      if (tempFile && filePath) {
+        try {
+          await Deno.remove(filePath);
+        } catch {
+          // Ignore cleanup errors
+        }
+      }
+
+      return this.jsonResponse({
+        success: true,
+        message: `Backup imported successfully as service '${result.service.name}'`,
+        data: {
+          service: result.service,
+          platformResourcesRestored: result.platformResourcesRestored,
+          warnings: result.warnings,
+        },
+      });
+    } catch (error) {
+      logger.error(`Failed to import backup: ${getErrorMessage(error)}`);
+      return this.jsonResponse({
+        success: false,
+        error: getErrorMessage(error) || 'Failed to import backup',
+      }, 500);
+    }
+  }
+
   /**
    * Set backup encryption password
    */