feat(menu): delete category/item + fix RTL availability toggle

- Add DELETE /api/cafes/{cafeId}/menu/items/{id} (DeleteItemAsync soft-delete,
  mirroring the existing category delete) — item delete had no backend route.
- Dashboard menu admin: destructive "delete" action in the item and category
  edit modals, behind a shared confirm dialog (AlertDialog). Deleting the
  selected category falls back to "all items".
- Fix the availability ToggleSwitch in RTL: force dir="ltr" so the knob's
  translate-x stays inside the track instead of escaping on the right
  (same fix as the admin-panel toggles).
- i18n: deleteItem/deleteCategory confirm + success strings (fa/en/ar).

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

src/Meezi.API/Services/MenuService.cs

@@ -16,6 +16,7 @@ public interface IMenuService
     Task<MenuItemDto?> CreateItemAsync(string cafeId, CreateMenuItemRequest request, CancellationToken cancellationToken = default);
     Task<MenuItemDto?> UpdateItemAsync(string cafeId, string id, UpdateMenuItemRequest request, CancellationToken cancellationToken = default);
     Task<MenuItemDto?> SetAvailabilityAsync(string cafeId, string id, bool isAvailable, CancellationToken cancellationToken = default);
+    Task<bool> DeleteItemAsync(string cafeId, string id, CancellationToken cancellationToken = default);
 }
 
 public class MenuService : IMenuService
@@ -192,6 +193,16 @@ public class MenuService : IMenuService
         return ToItemDto(entity);
     }
 
+    public async Task<bool> DeleteItemAsync(string cafeId, string id, CancellationToken cancellationToken = default)
+    {
+        var entity = await _db.MenuItems.FirstOrDefaultAsync(i => i.Id == id && i.CafeId == cafeId, cancellationToken);
+        if (entity is null) return false;
+
+        entity.DeletedAt = DateTime.UtcNow;
+        await _db.SaveChangesAsync(cancellationToken);
+        return true;
+    }
+
     private static string? NormalizeOptionalText(string? value) =>
         string.IsNullOrWhiteSpace(value) ? null : value.Trim();