feat: Add tiered packaging fee support for stores

Introduces tiered packaging fee configuration for stores by adding OrderPackagingFeeMode and PackagingFeeTiers fields to StoreFee. Updates DTOs, validators, handlers, and mapping logic to support both fixed and tiered packaging fee modes. Adds StoreFeeTierHelper for tier normalization and serialization, and includes a database migration to persist the new fields.

src/Application/TakeoutSaaS.Application/App/Stores/Handlers/GetStoreFeeQueryHandler.cs

@@ -41,6 +41,7 @@ public sealed class GetStoreFeeQueryHandler(
                 MinimumOrderAmount = 0m,
                 BaseDeliveryFee = 0m,
                 PackagingFeeMode = Domain.Stores.Enums.PackagingFeeMode.Fixed,
+                OrderPackagingFeeMode = Domain.Stores.Enums.OrderPackagingFeeMode.Fixed,
                 FixedPackagingFee = 0m
             };
             return StoreMapping.ToDto(fallback);