Moved to uv from poetry

Updated ruff and mypy, accepted all changes
Central exception management and injected the Session.
This removed a lot of duplicated boilerplate code.
Added health check
Updated to Angular 21

overlord/src/app/closing-stock/closing-stock.component.ts

@@ -77,7 +77,7 @@ export class ClosingStockComponent implements OnInit {
   costCentres: CostCentre[];
 
   @HostListener('window:keydown.f2', ['$event'])
-  focusDate(event: KeyboardEvent) {
+  focusDate(event: Event) {
     event.preventDefault();
     this.dateElement.nativeElement.focus();
     this.dateElement.nativeElement.select();