feat: filter digest tiles by user permissions and add import progress status

- Store UserGroups from OIDC in UserSettings entity, sync on each request
- Filter daily digest tiles based on user's permission groups
- Add in-memory job status tracking to EmailImportService
- Poll import job status in MailImportWizard and show progress in Spin tip

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

paperless-backend/src/database/entities/user-settings.entity.ts

@@ -38,6 +38,9 @@ export class UserSettings {
   @Column({ type: 'boolean', default: false })
   DailyDigestEnabled!: boolean;
 
+  @Column({ type: 'json', nullable: true })
+  UserGroups!: string[] | null;
+
   @Column({ type: 'varchar', length: 255, nullable: true })
   UserEmail!: string | null;