chore: apply ESLint auto-fix across entire backend

Reformats code style (line breaks, indentation, type annotations)
without changing logic. Also includes minor feature additions bundled
in the same lint run (stats service, user-settings groups, agrarmonitor
polling improvements).

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

paperless-backend/src/barcode/page-cache.service.ts

@@ -12,7 +12,10 @@ export class PageCacheService {
   private readonly inboxRoot: string;
 
   constructor(configService: ConfigService) {
-    this.inboxRoot = configService.get<string>('INBOX_DATA_DIR', '/mnt/data/inbox');
+    this.inboxRoot = configService.get<string>(
+      'INBOX_DATA_DIR',
+      '/mnt/data/inbox',
+    );
   }
 
   documentDir(documentId: string): string {
@@ -47,7 +50,10 @@ export class PageCacheService {
 
       try {
         await fs.copyFile(src, previewDest);
-        await sharp(src).resize({ width: THUMBNAIL_WIDTH }).png().toFile(thumbDest);
+        await sharp(src)
+          .resize({ width: THUMBNAIL_WIDTH })
+          .png()
+          .toFile(thumbDest);
       } catch (err: any) {
         this.logger.warn(
           `Seiten-Cache fehlgeschlagen (${documentId} Seite ${page}): ${err.message}`,