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>

backend/internal/domain/menu/repository.go

@@ -268,15 +268,15 @@ func (r *Repository) GetPlanIDByWeek(ctx context.Context, userID, weekStart stri
 	return id, nil
 }
 
-// GetIngredientsByPlan returns all ingredients from all recipes in the plan.
+// GetIngredientsByPlan returns all products from all recipes in the plan.
 func (r *Repository) GetIngredientsByPlan(ctx context.Context, planID string) ([]ingredientRow, error) {
 	rows, err := r.pool.Query(ctx, `
-		SELECT ri.name, ri.amount, ri.unit_code, mi.meal_type
+		SELECT rp.name, rp.amount, rp.unit_code, mi.meal_type
 		FROM menu_items mi
 		JOIN recipes rec ON rec.id = mi.recipe_id
-		JOIN recipe_ingredients ri ON ri.recipe_id = rec.id
+		JOIN recipe_products rp ON rp.recipe_id = rec.id
 		WHERE mi.menu_plan_id = $1
-		ORDER BY ri.sort_order`, planID)
+		ORDER BY rp.sort_order`, planID)
 	if err != nil {
 		return nil, fmt.Errorf("get ingredients by plan: %w", err)
 	}