feat(button): add disabled state input to stateful button component

libs/ui/buttons/src/lib/stateful-button/stateful-button.component.html

@@ -6,6 +6,7 @@
   (click)="handleButtonClick()"
   data-what="stateful-button"
   [attr.data-which]="state()"
+  [disabled]="disabled()"
 >
   @switch (state()) {
     @case ('default') {

libs/ui/buttons/src/lib/stateful-button/stateful-button.component.ts

@@ -81,6 +81,7 @@ export class StatefulButtonComponent implements OnDestroy {
   color = input<ButtonColor>('primary');
   size = input<ButtonSize>('medium');
   pending = input<boolean>(false);
+  disabled = input<boolean>(false);
 
   // Output events
   clicked = output<void>();