1┌─────────────────────────────────────────────────────────────┐
2│                     ShippingFacade                          │
3│                      (Facade Pattern)                       │
4│  Coordinates all subsystems and provides unified interface  │
5└────────┬────────────────────────────────────────────────────┘
6         │
7         ├──────► ValidationChain (Chain of Responsibility)
8         │        ├── FormatValidator
9         │        ├── PostalCodeValidator
10         │        ├── GeocodingValidator
11         │        └── DeliverabilityValidator
12         │
13         ├──────► RateService (Strategy Pattern)
14         │        ├── StandardRateStrategy
15         │        ├── ZoneBasedRateStrategy
16         │        └── VolumetricRateStrategy
17         │
18         ├──────► CarrierFactoryRegistry (Factory Method)
19         │        ├── USPSFactory → USPSService
20         │        ├── FedExFactory → FedExService
21         │        ├── UPSFactory → UPSService
22         │        └── DHLFactory → DHLService
23         │
24         ├──────► ShipmentDecorator (Decorator Pattern)
25         │        ├── InsuranceDecorator
26         │        ├── SignatureDecorator
27         │        ├── SaturdayDeliveryDecorator
28         │        └── TrackingNotificationDecorator
29         │
30         ├──────► OrderStateManager (State Pattern)
31         │        ├── PendingState
32         │        ├── ProcessingState
33         │        ├── ShippedState
34         │        ├── DeliveredState
35         │        └── CancelledState
36         │
37         └──────► TrackingNotifier (Observer Pattern)
38                  ├── EmailNotifier
39                  ├── SMSNotifier
40                  ├── WebhookNotifier
41                  └── PushNotifier