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/tests/userproduct/repository_integration_test.go

@@ -0,0 +1,137 @@
+//go:build integration
+
+package userproduct_test
+
+import (
+	"context"
+	"testing"
+
+	"github.com/food-ai/backend/internal/domain/userproduct"
+	"github.com/food-ai/backend/internal/testutil"
+)
+
+func TestUserProductRepository_Create_Defaults(t *testing.T) {
+	pool := testutil.SetupTestDB(t)
+	repo := userproduct.NewRepository(pool)
+	requestContext := context.Background()
+
+	// storage_days=0 → 7; unit="" → "pcs"; quantity=0 → 1
+	created, createError := repo.Create(requestContext, "test-user", userproduct.CreateRequest{
+		Name:        "Milk",
+		StorageDays: 0,
+		Unit:        "",
+		Quantity:    0,
+	})
+	if createError != nil {
+		t.Fatalf("create user product: %v", createError)
+	}
+	if created.StorageDays != 7 {
+		t.Errorf("expected storage_days=7, got %d", created.StorageDays)
+	}
+	if created.Unit != "pcs" {
+		t.Errorf("expected unit=pcs, got %q", created.Unit)
+	}
+	if created.Quantity != 1 {
+		t.Errorf("expected quantity=1, got %v", created.Quantity)
+	}
+}
+
+func TestUserProductRepository_List_OrderByExpiry(t *testing.T) {
+	pool := testutil.SetupTestDB(t)
+	repo := userproduct.NewRepository(pool)
+	requestContext := context.Background()
+
+	userID := "list-order-user"
+	_, createError := repo.Create(requestContext, userID, userproduct.CreateRequest{Name: "Milk", StorageDays: 14})
+	if createError != nil {
+		t.Fatalf("create Milk: %v", createError)
+	}
+	_, createError = repo.Create(requestContext, userID, userproduct.CreateRequest{Name: "Butter", StorageDays: 3})
+	if createError != nil {
+		t.Fatalf("create Butter: %v", createError)
+	}
+
+	products, listError := repo.List(requestContext, userID)
+	if listError != nil {
+		t.Fatalf("list user products: %v", listError)
+	}
+	if len(products) != 2 {
+		t.Fatalf("expected 2 products, got %d", len(products))
+	}
+	// Butter (3 days) should come before Milk (14 days).
+	if products[0].Name != "Butter" {
+		t.Errorf("expected first product Butter (expires sooner), got %q", products[0].Name)
+	}
+}
+
+func TestUserProductRepository_BatchCreate(t *testing.T) {
+	pool := testutil.SetupTestDB(t)
+	repo := userproduct.NewRepository(pool)
+	requestContext := context.Background()
+
+	products, batchError := repo.BatchCreate(requestContext, "batch-user", []userproduct.CreateRequest{
+		{Name: "Eggs", Quantity: 12, Unit: "pcs"},
+		{Name: "Flour", Quantity: 500, Unit: "g"},
+	})
+	if batchError != nil {
+		t.Fatalf("batch create: %v", batchError)
+	}
+	if len(products) != 2 {
+		t.Errorf("expected 2 products, got %d", len(products))
+	}
+}
+
+func TestUserProductRepository_Update_NotFound(t *testing.T) {
+	pool := testutil.SetupTestDB(t)
+	repo := userproduct.NewRepository(pool)
+	requestContext := context.Background()
+
+	newName := "Ghost"
+	_, updateError := repo.Update(requestContext, "00000000-0000-0000-0000-000000000000", "any-user",
+		userproduct.UpdateRequest{Name: &newName})
+	if updateError != userproduct.ErrNotFound {
+		t.Errorf("expected ErrNotFound, got %v", updateError)
+	}
+}
+
+func TestUserProductRepository_Delete_WrongUser(t *testing.T) {
+	pool := testutil.SetupTestDB(t)
+	repo := userproduct.NewRepository(pool)
+	requestContext := context.Background()
+
+	created, createError := repo.Create(requestContext, "owner-user", userproduct.CreateRequest{Name: "Cheese"})
+	if createError != nil {
+		t.Fatalf("create user product: %v", createError)
+	}
+
+	deleteError := repo.Delete(requestContext, created.ID, "other-user")
+	if deleteError != userproduct.ErrNotFound {
+		t.Errorf("expected ErrNotFound when deleting another user's product, got %v", deleteError)
+	}
+}
+
+func TestUserProductRepository_ListForPrompt(t *testing.T) {
+	pool := testutil.SetupTestDB(t)
+	repo := userproduct.NewRepository(pool)
+	requestContext := context.Background()
+
+	userID := "prompt-user"
+	_, createError := repo.Create(requestContext, userID, userproduct.CreateRequest{
+		Name: "Tomatoes", Quantity: 4, Unit: "pcs", StorageDays: 5,
+	})
+	if createError != nil {
+		t.Fatalf("create user product: %v", createError)
+	}
+
+	lines, listError := repo.ListForPrompt(requestContext, userID)
+	if listError != nil {
+		t.Fatalf("list for prompt: %v", listError)
+	}
+	if len(lines) != 1 {
+		t.Fatalf("expected 1 line, got %d", len(lines))
+	}
+	// Line should start with "- Tomatoes".
+	if len(lines[0]) < 11 || lines[0][:11] != "- Tomatoes " {
+		t.Errorf("unexpected prompt line format: %q", lines[0])
+	}
+}