JSON serialization

In Dart, JSON arrives as a Map<String, dynamic>, which is a type-unsafe shape: write json['naem'] and the compiler stays silent while the failure waits for runtime.

The fix is converting to a domain model at the boundary. Two routes:

• By hand — factory Order.fromJson(Map<String, dynamic> json). No dependency, but tedious and error-prone as the model grows
• Code generation — json_serializable with build_runner: you write annotations and fromJson/toJson are generated

Either way the conversion belongs in the data layer only; a widget should never see JSON.

Two situations always cause trouble with real APIs:

• `null` and missing fields — the docs may say "always present", but in practice it will not be. Reflect nullability honestly in the model and supply defaults
• Type mismatches — a backend sometimes sends a number as a string ("42"). A blind as int cast explodes at runtime; a safe parse helper is needed

These are among the most common findings in API testing, and on the Flutter side they are handled with defensive parsing.