feat: rename ingredients→products, products→user_products; add barcode/OFF import

- Rename catalog: ingredient/* → product/* (canonical_name, barcode, nutrition per 100g)
- Rename pantry: product/* → userproduct/* (user-owned items with expiry)
- Squash migrations into single 001_initial_schema.sql (clean-db baseline)
- product_categories: add English canonical name column; fix COALESCE in queries
- Remove product_translations: product names are stored in their original language
- Add default_unit_name to product API responses via unit_translations JOIN
- Add cmd/importoff: bulk import from OpenFoodFacts JSONL dump (COPY + ON CONFLICT)
- Diary: support product_id entries alongside dish_id (CHECK num_nonnulls = 1)
- Home: getLoggedCalories joins both recipes and catalog products
- Flutter: rename models/providers/services to match backend rename
- Flutter: add barcode scan flow for diary (mobile_scanner, product_portion_sheet)
- Flutter: localise 6 new keys across 12 languages (barcode scan, portion weight)
- Routes: GET /products/search, GET /products/barcode/{barcode}, /user-products

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

client/lib/shared/models/product.g.dart

@@ -6,32 +6,32 @@ part of 'product.dart';
 // JsonSerializableGenerator
 // **************************************************************************
 
-Product _$ProductFromJson(Map<String, dynamic> json) => Product(
-  id: json['id'] as String,
-  userId: json['user_id'] as String,
-  mappingId: json['mapping_id'] as String?,
-  name: json['name'] as String,
-  quantity: (json['quantity'] as num).toDouble(),
-  unit: json['unit'] as String,
-  category: json['category'] as String?,
-  storageDays: (json['storage_days'] as num).toInt(),
-  addedAt: DateTime.parse(json['added_at'] as String),
-  expiresAt: DateTime.parse(json['expires_at'] as String),
-  daysLeft: (json['days_left'] as num).toInt(),
-  expiringSoon: json['expiring_soon'] as bool,
-);
+CatalogProduct _$CatalogProductFromJson(Map<String, dynamic> json) =>
+    CatalogProduct(
+      id: json['id'] as String,
+      canonicalName: json['canonical_name'] as String,
+      categoryName: json['category_name'] as String?,
+      category: json['category'] as String?,
+      defaultUnit: json['default_unit'] as String?,
+      storageDays: (json['storage_days'] as num?)?.toInt(),
+      barcode: json['barcode'] as String?,
+      caloriesPer100g: (json['calories_per_100g'] as num?)?.toDouble(),
+      proteinPer100g: (json['protein_per_100g'] as num?)?.toDouble(),
+      fatPer100g: (json['fat_per_100g'] as num?)?.toDouble(),
+      carbsPer100g: (json['carbs_per_100g'] as num?)?.toDouble(),
+    );
 
-Map<String, dynamic> _$ProductToJson(Product instance) => <String, dynamic>{
-  'id': instance.id,
-  'user_id': instance.userId,
-  'mapping_id': instance.mappingId,
-  'name': instance.name,
-  'quantity': instance.quantity,
-  'unit': instance.unit,
-  'category': instance.category,
-  'storage_days': instance.storageDays,
-  'added_at': instance.addedAt.toIso8601String(),
-  'expires_at': instance.expiresAt.toIso8601String(),
-  'days_left': instance.daysLeft,
-  'expiring_soon': instance.expiringSoon,
-};
+Map<String, dynamic> _$CatalogProductToJson(CatalogProduct instance) =>
+    <String, dynamic>{
+      'id': instance.id,
+      'canonical_name': instance.canonicalName,
+      'category_name': instance.categoryName,
+      'category': instance.category,
+      'default_unit': instance.defaultUnit,
+      'storage_days': instance.storageDays,
+      'barcode': instance.barcode,
+      'calories_per_100g': instance.caloriesPer100g,
+      'protein_per_100g': instance.proteinPer100g,
+      'fat_per_100g': instance.fatPer100g,
+      'carbs_per_100g': instance.carbsPer100g,
+    };