refactor: удалить мёртвые таблицы qt_price_overrides, qt_pricing_alerts, qt_component_usage_stats

Удалены модели, репозитории и авто-миграции для трёх таблиц, которые
никогда не использовались в продакшн-коде. Убраны StatsRepository и
RecordUsage из сервисов, сигнатуры конструкторов упрощены.

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

internal/services/quote.go

@@ -19,7 +19,6 @@ var (
 
 type QuoteService struct {
 	componentRepo  *repository.ComponentRepository
-	statsRepo      *repository.StatsRepository
 	pricelistRepo  *repository.PricelistRepository
 	localDB        *localdb.LocalDB
 	pricingService priceResolver
@@ -34,14 +33,12 @@ type priceResolver interface {
 
 func NewQuoteService(
 	componentRepo *repository.ComponentRepository,
-	statsRepo *repository.StatsRepository,
 	pricelistRepo *repository.PricelistRepository,
 	localDB *localdb.LocalDB,
 	pricingService priceResolver,
 ) *QuoteService {
 	return &QuoteService{
 		componentRepo:  componentRepo,
-		statsRepo:      statsRepo,
 		pricelistRepo:  pricelistRepo,
 		localDB:        localDB,
 		pricingService: pricingService,
@@ -504,18 +501,3 @@ func (s *QuoteService) lookupPriceByPricelistID(pricelistID uint, lotName string
 	return 0, false
 }
 
-// RecordUsage records that components were used in a quote
-func (s *QuoteService) RecordUsage(items []models.ConfigItem) error {
-	if s.statsRepo == nil {
-		// Offline mode: usage stats are unavailable and should not block config saves.
-		return nil
-	}
-
-	for _, item := range items {
-		revenue := item.UnitPrice * float64(item.Quantity)
-		if err := s.statsRepo.IncrementUsage(item.LotName, item.Quantity, revenue); err != nil {
-			return err
-		}
-	}
-	return nil
-}