feat(admin): implement pricing overrides for plans and update pricing logic

apps/frontend/src/features/onboard/components/steps/plan-select-step.tsx

@@ -58,7 +58,11 @@ export function PlanSelectStep({ form, plans }: PlanSelectStepProps) {
               <div className="mb-3">
                 <h3 className="text-xl font-bold">{plan.name}</h3>
                 <div className="mt-1">
-                  <span className="text-3xl font-bold">${plan.price}</span>
+                  <span className="text-3xl font-bold">
+                    {plan.currency === 'ARS'
+                      ? `AR$${plan.price.toLocaleString('es-AR')}`
+                      : `$${plan.price.toFixed(2)}`}
+                  </span>
                   <span className="text-sm text-muted-foreground">/mes</span>
                 </div>
               </div>