Fix mobile UI bugs from screenshots

- Notifications panel: fixed positioning on mobile (full-width below topbar,
  no more overflow behind calendar)
- BookingModal: two-column layout stacks vertically on mobile (flex-col sm:flex-row)
- TariffsPage cards: price + actions merged into right column, no text overlap
- DiscountsPage cards: same fix, price text reduced to text-lg
- ReviewsPage: action buttons moved inside content div (no longer overlap guest name)
- RoomCategoriesPage: edit/delete buttons stack as column, 'Номера' text hidden on mobile
- PosPage: show desktop-only message on mobile instead of broken layout

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

src/pages/DiscountsPage.tsx

@@ -376,18 +376,15 @@ export function DiscountsPage() {
               </div>
             </div>
 
-            {/* Value badge */}
-            <div className="text-right shrink-0">
+            {/* Value + Actions (right column) */}
+            <div className="shrink-0 flex flex-col items-end gap-2">
               <p className={cn(
-                'text-xl font-bold',
+                'text-lg font-bold',
                 discount.value === 100 ? 'text-emerald-600 dark:text-emerald-400' : 'text-brand-600 dark:text-brand-400',
               )}>
                 {discount.value === 100 ? 'Бесплатно' : `−${discount.value}${discount.valueType === 'percent' ? '%' : ' ₽'}`}
               </p>
-            </div>
-
-            {/* Actions */}
-            <div className="flex items-center gap-1 shrink-0">
+              <div className="flex items-center gap-1">
               <button
                 onClick={() => toggleActive(discount.id)}
                 className={cn('p-1.5 rounded-lg transition-colors', discount.isActive ? 'text-brand-600' : 'text-slate-400')}
@@ -402,6 +399,7 @@ export function DiscountsPage() {
                 className="p-1.5 rounded-lg text-slate-400 hover:text-red-600 hover:bg-red-50 dark:hover:bg-red-900/20 transition-colors">
                 <Trash2 size={15} />
               </button>
+              </div>
             </div>
           </div>
         ))}