refactor: migrate ingredient aliases/categories to dedicated tables, drop spoonacular_id

- migration 012: create ingredient_categories + ingredient_category_translations
  tables (7 slugs, Russian names); add ingredient_aliases (ingredient_id, lang,
  alias) with GIN trigram index; migrate aliases JSONB from ingredient_mappings
  and ingredient_translations; drop aliases columns and spoonacular_id; add
  UNIQUE (canonical_name) as conflict key
- ingredient/model: remove SpoonacularID, add CategoryName for localized display
- ingredient/repository: conflict on canonical_name; GetByID/Search join category
  translations and aliases lateral; new UpsertAliases (pgx batch),
  UpsertCategoryTranslation; remove GetBySpoonacularID; split scan helpers into
  scanMappingWrite / scanMappingRead
- gemini/recognition: add IngredientTranslation type; IngredientClassification
  now carries Translations []IngredientTranslation instead of CanonicalNameRu;
  update ClassifyIngredient prompt to English with structured translations array
- recognition/handler: update ingredientRepo interface; saveClassification uses
  UpsertAliases and iterates Translations
- recipe/model: remove SpoonacularID from RecipeIngredient
- integration tests: remove SpoonacularID fixtures, replace GetBySpoonacularID
  tests with GetByID, add UpsertAliases and UpsertCategoryTranslation tests
- Flutter: remove canonicalNameRu from IngredientMapping, add categoryName;
  displayName returns server-resolved canonicalName; regenerate .g.dart

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

backend/internal/recognition/handler.go

@@ -17,7 +17,8 @@ import (
 type ingredientRepo interface {
 	FuzzyMatch(ctx context.Context, name string) (*ingredient.IngredientMapping, error)
 	Upsert(ctx context.Context, m *ingredient.IngredientMapping) (*ingredient.IngredientMapping, error)
-	UpsertTranslation(ctx context.Context, id, lang, name string, aliases json.RawMessage) error
+	UpsertTranslation(ctx context.Context, id, lang, name string) error
+	UpsertAliases(ctx context.Context, id, lang string, aliases []string) error
 }
 
 // Handler handles POST /ai/* recognition endpoints.
@@ -212,11 +213,6 @@ func (h *Handler) saveClassification(ctx context.Context, c *gemini.IngredientCl
 		return nil
 	}
 
-	aliasesJSON, err := json.Marshal(c.Aliases)
-	if err != nil {
-		return nil
-	}
-
 	m := &ingredient.IngredientMapping{
 		CanonicalName:   c.CanonicalName,
 		Category:        strPtr(c.Category),
@@ -226,7 +222,6 @@ func (h *Handler) saveClassification(ctx context.Context, c *gemini.IngredientCl
 		FatPer100g:      c.FatPer100g,
 		CarbsPer100g:    c.CarbsPer100g,
 		StorageDays:     intPtr(c.StorageDays),
-		Aliases:         aliasesJSON,
 	}
 
 	saved, err := h.ingredientRepo.Upsert(ctx, m)
@@ -235,12 +230,23 @@ func (h *Handler) saveClassification(ctx context.Context, c *gemini.IngredientCl
 		return nil
 	}
 
-	// Persist the Russian translation when Gemini provided one.
-	if c.CanonicalNameRu != "" {
-		if err := h.ingredientRepo.UpsertTranslation(ctx, saved.ID, "ru", c.CanonicalNameRu, json.RawMessage("[]")); err != nil {
-			slog.Warn("upsert ingredient translation", "id", saved.ID, "err", err)
+	if len(c.Aliases) > 0 {
+		if err := h.ingredientRepo.UpsertAliases(ctx, saved.ID, "en", c.Aliases); err != nil {
+			slog.Warn("upsert ingredient aliases", "id", saved.ID, "err", err)
 		}
 	}
+
+	for _, t := range c.Translations {
+		if err := h.ingredientRepo.UpsertTranslation(ctx, saved.ID, t.Lang, t.Name); err != nil {
+			slog.Warn("upsert ingredient translation", "id", saved.ID, "lang", t.Lang, "err", err)
+		}
+		if len(t.Aliases) > 0 {
+			if err := h.ingredientRepo.UpsertAliases(ctx, saved.ID, t.Lang, t.Aliases); err != nil {
+				slog.Warn("upsert ingredient translation aliases", "id", saved.ID, "lang", t.Lang, "err", err)
+			}
+		}
+	}
+
 	return saved
 }