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/inbox-postprocessor/variable-resolver.ts

@@ -58,7 +58,10 @@ export function buildVariables(ctx: ResolverContext): Record<string, string> {
  * Ersetzt Platzhalter der Form `{name}` und `{name.group}` im Template.
  * Unbekannte Platzhalter bleiben unverändert.
  */
-export function applyTemplate(template: string, vars: Record<string, string>): string {
+export function applyTemplate(
+  template: string,
+  vars: Record<string, string>,
+): string {
   if (!template) return template;
   return template.replace(/\{([A-Za-z0-9_.]+)\}/g, (full, name: string) => {
     return name in vars ? vars[name] : full;