feat: dukung penjualan produk per timbangan

Produk kini punya cara jual `unit` (cacah) atau `weight` (timbangan),
mengikuti kontrak backend di docs/integration-weight-based-products.md.

- tipe SellBy, domain/infrastructure unit baru, dan endpoint /api/v1/units
- dialog input berat saat produk timbangan ditambahkan ke keranjang
- tiap penimbangan jadi baris keranjang sendiri; total baris dihitung
  berat x harga satuan, sedangkan produk cacah tetap digabung
- request ke backend mengirim quantity 1 dan membawa berat
- migrasi DB v3: kolom sell_by, unit_id, unit_name, unit_abbreviation
  di tabel products supaya satuan tetap tampil saat offline
- tampilan keranjang, struk, split bill, void, dan refund memakai berat
- test/weight_based_products_test.dart menutup perilaku di atas (9 test)

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

lib/infrastructure/product/product_dtos.freezed.dart

@@ -293,6 +293,223 @@ abstract class _ListProductDto extends ListProductDto {
       throw _privateConstructorUsedError;
 }
 
+ProductUnitDto _$ProductUnitDtoFromJson(Map<String, dynamic> json) {
+  return _ProductUnitDto.fromJson(json);
+}
+
+/// @nodoc
+mixin _$ProductUnitDto {
+  @JsonKey(name: "id")
+  String? get id => throw _privateConstructorUsedError;
+  @JsonKey(name: "name")
+  String? get name => throw _privateConstructorUsedError;
+  @JsonKey(name: "abbreviation")
+  String? get abbreviation => throw _privateConstructorUsedError;
+
+  /// Serializes this ProductUnitDto to a JSON map.
+  Map<String, dynamic> toJson() => throw _privateConstructorUsedError;
+
+  /// Create a copy of ProductUnitDto
+  /// with the given fields replaced by the non-null parameter values.
+  @JsonKey(includeFromJson: false, includeToJson: false)
+  $ProductUnitDtoCopyWith<ProductUnitDto> get copyWith =>
+      throw _privateConstructorUsedError;
+}
+
+/// @nodoc
+abstract class $ProductUnitDtoCopyWith<$Res> {
+  factory $ProductUnitDtoCopyWith(
+    ProductUnitDto value,
+    $Res Function(ProductUnitDto) then,
+  ) = _$ProductUnitDtoCopyWithImpl<$Res, ProductUnitDto>;
+  @useResult
+  $Res call({
+    @JsonKey(name: "id") String? id,
+    @JsonKey(name: "name") String? name,
+    @JsonKey(name: "abbreviation") String? abbreviation,
+  });
+}
+
+/// @nodoc
+class _$ProductUnitDtoCopyWithImpl<$Res, $Val extends ProductUnitDto>
+    implements $ProductUnitDtoCopyWith<$Res> {
+  _$ProductUnitDtoCopyWithImpl(this._value, this._then);
+
+  // ignore: unused_field
+  final $Val _value;
+  // ignore: unused_field
+  final $Res Function($Val) _then;
+
+  /// Create a copy of ProductUnitDto
+  /// with the given fields replaced by the non-null parameter values.
+  @pragma('vm:prefer-inline')
+  @override
+  $Res call({
+    Object? id = freezed,
+    Object? name = freezed,
+    Object? abbreviation = freezed,
+  }) {
+    return _then(
+      _value.copyWith(
+            id: freezed == id
+                ? _value.id
+                : id // ignore: cast_nullable_to_non_nullable
+                      as String?,
+            name: freezed == name
+                ? _value.name
+                : name // ignore: cast_nullable_to_non_nullable
+                      as String?,
+            abbreviation: freezed == abbreviation
+                ? _value.abbreviation
+                : abbreviation // ignore: cast_nullable_to_non_nullable
+                      as String?,
+          )
+          as $Val,
+    );
+  }
+}
+
+/// @nodoc
+abstract class _$$ProductUnitDtoImplCopyWith<$Res>
+    implements $ProductUnitDtoCopyWith<$Res> {
+  factory _$$ProductUnitDtoImplCopyWith(
+    _$ProductUnitDtoImpl value,
+    $Res Function(_$ProductUnitDtoImpl) then,
+  ) = __$$ProductUnitDtoImplCopyWithImpl<$Res>;
+  @override
+  @useResult
+  $Res call({
+    @JsonKey(name: "id") String? id,
+    @JsonKey(name: "name") String? name,
+    @JsonKey(name: "abbreviation") String? abbreviation,
+  });
+}
+
+/// @nodoc
+class __$$ProductUnitDtoImplCopyWithImpl<$Res>
+    extends _$ProductUnitDtoCopyWithImpl<$Res, _$ProductUnitDtoImpl>
+    implements _$$ProductUnitDtoImplCopyWith<$Res> {
+  __$$ProductUnitDtoImplCopyWithImpl(
+    _$ProductUnitDtoImpl _value,
+    $Res Function(_$ProductUnitDtoImpl) _then,
+  ) : super(_value, _then);
+
+  /// Create a copy of ProductUnitDto
+  /// with the given fields replaced by the non-null parameter values.
+  @pragma('vm:prefer-inline')
+  @override
+  $Res call({
+    Object? id = freezed,
+    Object? name = freezed,
+    Object? abbreviation = freezed,
+  }) {
+    return _then(
+      _$ProductUnitDtoImpl(
+        id: freezed == id
+            ? _value.id
+            : id // ignore: cast_nullable_to_non_nullable
+                  as String?,
+        name: freezed == name
+            ? _value.name
+            : name // ignore: cast_nullable_to_non_nullable
+                  as String?,
+        abbreviation: freezed == abbreviation
+            ? _value.abbreviation
+            : abbreviation // ignore: cast_nullable_to_non_nullable
+                  as String?,
+      ),
+    );
+  }
+}
+
+/// @nodoc
+@JsonSerializable()
+class _$ProductUnitDtoImpl extends _ProductUnitDto {
+  const _$ProductUnitDtoImpl({
+    @JsonKey(name: "id") this.id,
+    @JsonKey(name: "name") this.name,
+    @JsonKey(name: "abbreviation") this.abbreviation,
+  }) : super._();
+
+  factory _$ProductUnitDtoImpl.fromJson(Map<String, dynamic> json) =>
+      _$$ProductUnitDtoImplFromJson(json);
+
+  @override
+  @JsonKey(name: "id")
+  final String? id;
+  @override
+  @JsonKey(name: "name")
+  final String? name;
+  @override
+  @JsonKey(name: "abbreviation")
+  final String? abbreviation;
+
+  @override
+  String toString() {
+    return 'ProductUnitDto(id: $id, name: $name, abbreviation: $abbreviation)';
+  }
+
+  @override
+  bool operator ==(Object other) {
+    return identical(this, other) ||
+        (other.runtimeType == runtimeType &&
+            other is _$ProductUnitDtoImpl &&
+            (identical(other.id, id) || other.id == id) &&
+            (identical(other.name, name) || other.name == name) &&
+            (identical(other.abbreviation, abbreviation) ||
+                other.abbreviation == abbreviation));
+  }
+
+  @JsonKey(includeFromJson: false, includeToJson: false)
+  @override
+  int get hashCode => Object.hash(runtimeType, id, name, abbreviation);
+
+  /// Create a copy of ProductUnitDto
+  /// with the given fields replaced by the non-null parameter values.
+  @JsonKey(includeFromJson: false, includeToJson: false)
+  @override
+  @pragma('vm:prefer-inline')
+  _$$ProductUnitDtoImplCopyWith<_$ProductUnitDtoImpl> get copyWith =>
+      __$$ProductUnitDtoImplCopyWithImpl<_$ProductUnitDtoImpl>(
+        this,
+        _$identity,
+      );
+
+  @override
+  Map<String, dynamic> toJson() {
+    return _$$ProductUnitDtoImplToJson(this);
+  }
+}
+
+abstract class _ProductUnitDto extends ProductUnitDto {
+  const factory _ProductUnitDto({
+    @JsonKey(name: "id") final String? id,
+    @JsonKey(name: "name") final String? name,
+    @JsonKey(name: "abbreviation") final String? abbreviation,
+  }) = _$ProductUnitDtoImpl;
+  const _ProductUnitDto._() : super._();
+
+  factory _ProductUnitDto.fromJson(Map<String, dynamic> json) =
+      _$ProductUnitDtoImpl.fromJson;
+
+  @override
+  @JsonKey(name: "id")
+  String? get id;
+  @override
+  @JsonKey(name: "name")
+  String? get name;
+  @override
+  @JsonKey(name: "abbreviation")
+  String? get abbreviation;
+
+  /// Create a copy of ProductUnitDto
+  /// with the given fields replaced by the non-null parameter values.
+  @override
+  @JsonKey(includeFromJson: false, includeToJson: false)
+  _$$ProductUnitDtoImplCopyWith<_$ProductUnitDtoImpl> get copyWith =>
+      throw _privateConstructorUsedError;
+}
+
 ProductDto _$ProductDtoFromJson(Map<String, dynamic> json) {
   return _ProductDto.fromJson(json);
 }
@@ -333,6 +550,16 @@ mixin _$ProductDto {
   String? get updatedAt => throw _privateConstructorUsedError;
   @JsonKey(name: "variants")
   List<ProductVariantDto>? get variants => throw _privateConstructorUsedError;
+  @JsonKey(name: "sell_by")
+  String? get sellBy => throw _privateConstructorUsedError;
+  @JsonKey(name: "unit_id")
+  String? get unitId => throw _privateConstructorUsedError;
+  @JsonKey(name: "unit_name")
+  String? get unitName => throw _privateConstructorUsedError;
+  @JsonKey(name: "unit_abbreviation")
+  String? get unitAbbreviation => throw _privateConstructorUsedError;
+  @JsonKey(name: "unit")
+  ProductUnitDto? get unit => throw _privateConstructorUsedError;
 
   /// Serializes this ProductDto to a JSON map.
   Map<String, dynamic> toJson() => throw _privateConstructorUsedError;
@@ -369,7 +596,14 @@ abstract class $ProductDtoCopyWith<$Res> {
     @JsonKey(name: "created_at") String? createdAt,
     @JsonKey(name: "updated_at") String? updatedAt,
     @JsonKey(name: "variants") List<ProductVariantDto>? variants,
+    @JsonKey(name: "sell_by") String? sellBy,
+    @JsonKey(name: "unit_id") String? unitId,
+    @JsonKey(name: "unit_name") String? unitName,
+    @JsonKey(name: "unit_abbreviation") String? unitAbbreviation,
+    @JsonKey(name: "unit") ProductUnitDto? unit,
   });
+
+  $ProductUnitDtoCopyWith<$Res>? get unit;
 }
 
 /// @nodoc
@@ -404,6 +638,11 @@ class _$ProductDtoCopyWithImpl<$Res, $Val extends ProductDto>
     Object? createdAt = freezed,
     Object? updatedAt = freezed,
     Object? variants = freezed,
+    Object? sellBy = freezed,
+    Object? unitId = freezed,
+    Object? unitName = freezed,
+    Object? unitAbbreviation = freezed,
+    Object? unit = freezed,
   }) {
     return _then(
       _value.copyWith(
@@ -475,10 +714,44 @@ class _$ProductDtoCopyWithImpl<$Res, $Val extends ProductDto>
                 ? _value.variants
                 : variants // ignore: cast_nullable_to_non_nullable
                       as List<ProductVariantDto>?,
+            sellBy: freezed == sellBy
+                ? _value.sellBy
+                : sellBy // ignore: cast_nullable_to_non_nullable
+                      as String?,
+            unitId: freezed == unitId
+                ? _value.unitId
+                : unitId // ignore: cast_nullable_to_non_nullable
+                      as String?,
+            unitName: freezed == unitName
+                ? _value.unitName
+                : unitName // ignore: cast_nullable_to_non_nullable
+                      as String?,
+            unitAbbreviation: freezed == unitAbbreviation
+                ? _value.unitAbbreviation
+                : unitAbbreviation // ignore: cast_nullable_to_non_nullable
+                      as String?,
+            unit: freezed == unit
+                ? _value.unit
+                : unit // ignore: cast_nullable_to_non_nullable
+                      as ProductUnitDto?,
           )
           as $Val,
     );
   }
+
+  /// Create a copy of ProductDto
+  /// with the given fields replaced by the non-null parameter values.
+  @override
+  @pragma('vm:prefer-inline')
+  $ProductUnitDtoCopyWith<$Res>? get unit {
+    if (_value.unit == null) {
+      return null;
+    }
+
+    return $ProductUnitDtoCopyWith<$Res>(_value.unit!, (value) {
+      return _then(_value.copyWith(unit: value) as $Val);
+    });
+  }
 }
 
 /// @nodoc
@@ -508,7 +781,15 @@ abstract class _$$ProductDtoImplCopyWith<$Res>
     @JsonKey(name: "created_at") String? createdAt,
     @JsonKey(name: "updated_at") String? updatedAt,
     @JsonKey(name: "variants") List<ProductVariantDto>? variants,
+    @JsonKey(name: "sell_by") String? sellBy,
+    @JsonKey(name: "unit_id") String? unitId,
+    @JsonKey(name: "unit_name") String? unitName,
+    @JsonKey(name: "unit_abbreviation") String? unitAbbreviation,
+    @JsonKey(name: "unit") ProductUnitDto? unit,
   });
+
+  @override
+  $ProductUnitDtoCopyWith<$Res>? get unit;
 }
 
 /// @nodoc
@@ -542,6 +823,11 @@ class __$$ProductDtoImplCopyWithImpl<$Res>
     Object? createdAt = freezed,
     Object? updatedAt = freezed,
     Object? variants = freezed,
+    Object? sellBy = freezed,
+    Object? unitId = freezed,
+    Object? unitName = freezed,
+    Object? unitAbbreviation = freezed,
+    Object? unit = freezed,
   }) {
     return _then(
       _$ProductDtoImpl(
@@ -613,6 +899,26 @@ class __$$ProductDtoImplCopyWithImpl<$Res>
             ? _value._variants
             : variants // ignore: cast_nullable_to_non_nullable
                   as List<ProductVariantDto>?,
+        sellBy: freezed == sellBy
+            ? _value.sellBy
+            : sellBy // ignore: cast_nullable_to_non_nullable
+                  as String?,
+        unitId: freezed == unitId
+            ? _value.unitId
+            : unitId // ignore: cast_nullable_to_non_nullable
+                  as String?,
+        unitName: freezed == unitName
+            ? _value.unitName
+            : unitName // ignore: cast_nullable_to_non_nullable
+                  as String?,
+        unitAbbreviation: freezed == unitAbbreviation
+            ? _value.unitAbbreviation
+            : unitAbbreviation // ignore: cast_nullable_to_non_nullable
+                  as String?,
+        unit: freezed == unit
+            ? _value.unit
+            : unit // ignore: cast_nullable_to_non_nullable
+                  as ProductUnitDto?,
       ),
     );
   }
@@ -639,6 +945,11 @@ class _$ProductDtoImpl extends _ProductDto {
     @JsonKey(name: "created_at") this.createdAt,
     @JsonKey(name: "updated_at") this.updatedAt,
     @JsonKey(name: "variants") final List<ProductVariantDto>? variants,
+    @JsonKey(name: "sell_by") this.sellBy,
+    @JsonKey(name: "unit_id") this.unitId,
+    @JsonKey(name: "unit_name") this.unitName,
+    @JsonKey(name: "unit_abbreviation") this.unitAbbreviation,
+    @JsonKey(name: "unit") this.unit,
   }) : _metadata = metadata,
        _variants = variants,
        super._();
@@ -713,9 +1024,25 @@ class _$ProductDtoImpl extends _ProductDto {
     return EqualUnmodifiableListView(value);
   }
 
+  @override
+  @JsonKey(name: "sell_by")
+  final String? sellBy;
+  @override
+  @JsonKey(name: "unit_id")
+  final String? unitId;
+  @override
+  @JsonKey(name: "unit_name")
+  final String? unitName;
+  @override
+  @JsonKey(name: "unit_abbreviation")
+  final String? unitAbbreviation;
+  @override
+  @JsonKey(name: "unit")
+  final ProductUnitDto? unit;
+
   @override
   String toString() {
-    return 'ProductDto(id: $id, organizationId: $organizationId, categoryId: $categoryId, sku: $sku, name: $name, description: $description, price: $price, cost: $cost, businessType: $businessType, imageUrl: $imageUrl, printerType: $printerType, printToChecker: $printToChecker, metadata: $metadata, isActive: $isActive, createdAt: $createdAt, updatedAt: $updatedAt, variants: $variants)';
+    return 'ProductDto(id: $id, organizationId: $organizationId, categoryId: $categoryId, sku: $sku, name: $name, description: $description, price: $price, cost: $cost, businessType: $businessType, imageUrl: $imageUrl, printerType: $printerType, printToChecker: $printToChecker, metadata: $metadata, isActive: $isActive, createdAt: $createdAt, updatedAt: $updatedAt, variants: $variants, sellBy: $sellBy, unitId: $unitId, unitName: $unitName, unitAbbreviation: $unitAbbreviation, unit: $unit)';
   }
 
   @override
@@ -749,12 +1076,19 @@ class _$ProductDtoImpl extends _ProductDto {
                 other.createdAt == createdAt) &&
             (identical(other.updatedAt, updatedAt) ||
                 other.updatedAt == updatedAt) &&
-            const DeepCollectionEquality().equals(other._variants, _variants));
+            const DeepCollectionEquality().equals(other._variants, _variants) &&
+            (identical(other.sellBy, sellBy) || other.sellBy == sellBy) &&
+            (identical(other.unitId, unitId) || other.unitId == unitId) &&
+            (identical(other.unitName, unitName) ||
+                other.unitName == unitName) &&
+            (identical(other.unitAbbreviation, unitAbbreviation) ||
+                other.unitAbbreviation == unitAbbreviation) &&
+            (identical(other.unit, unit) || other.unit == unit));
   }
 
   @JsonKey(includeFromJson: false, includeToJson: false)
   @override
-  int get hashCode => Object.hash(
+  int get hashCode => Object.hashAll([
     runtimeType,
     id,
     organizationId,
@@ -773,7 +1107,12 @@ class _$ProductDtoImpl extends _ProductDto {
     createdAt,
     updatedAt,
     const DeepCollectionEquality().hash(_variants),
-  );
+    sellBy,
+    unitId,
+    unitName,
+    unitAbbreviation,
+    unit,
+  ]);
 
   /// Create a copy of ProductDto
   /// with the given fields replaced by the non-null parameter values.
@@ -808,6 +1147,11 @@ abstract class _ProductDto extends ProductDto {
     @JsonKey(name: "created_at") final String? createdAt,
     @JsonKey(name: "updated_at") final String? updatedAt,
     @JsonKey(name: "variants") final List<ProductVariantDto>? variants,
+    @JsonKey(name: "sell_by") final String? sellBy,
+    @JsonKey(name: "unit_id") final String? unitId,
+    @JsonKey(name: "unit_name") final String? unitName,
+    @JsonKey(name: "unit_abbreviation") final String? unitAbbreviation,
+    @JsonKey(name: "unit") final ProductUnitDto? unit,
   }) = _$ProductDtoImpl;
   const _ProductDto._() : super._();
 
@@ -865,6 +1209,21 @@ abstract class _ProductDto extends ProductDto {
   @override
   @JsonKey(name: "variants")
   List<ProductVariantDto>? get variants;
+  @override
+  @JsonKey(name: "sell_by")
+  String? get sellBy;
+  @override
+  @JsonKey(name: "unit_id")
+  String? get unitId;
+  @override
+  @JsonKey(name: "unit_name")
+  String? get unitName;
+  @override
+  @JsonKey(name: "unit_abbreviation")
+  String? get unitAbbreviation;
+  @override
+  @JsonKey(name: "unit")
+  ProductUnitDto? get unit;
 
   /// Create a copy of ProductDto
   /// with the given fields replaced by the non-null parameter values.