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/app.module.ts

@@ -28,8 +28,8 @@ import * as path from 'path';
     ConfigModule.forRoot({
       isGlobal: true,
       envFilePath: [
-        path.resolve(__dirname, '../../.env'),   // Root .env (zentral)
-        path.resolve(__dirname, '../.env'),       // Lokale .env (Fallback)
+        path.resolve(__dirname, '../../.env'), // Root .env (zentral)
+        path.resolve(__dirname, '../.env'), // Lokale .env (Fallback)
       ],
     }),
     ScheduleModule.forRoot(),