refactor: migrate sync service and handlers to use ConnectionManager

Updated sync-related code to use ConnectionManager instead of direct
database references:

- SyncService now creates repositories on-demand when connection available
- SyncHandler uses ConnectionManager for lazy DB access
- Added ComponentFilter and ListComponents to localdb for offline queries
- All sync operations check connection status before attempting MariaDB access

This completes the transition to offline-first architecture where all
database access goes through ConnectionManager.

Part of Phase 2.5: Full Offline Mode

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

internal/localdb/components.go

@@ -9,6 +9,13 @@ import (
 	"gorm.io/gorm"
 )
 
+// ComponentFilter for searching with filters
+type ComponentFilter struct {
+	Category string
+	Search   string
+	HasPrice bool
+}
+
 // ComponentSyncResult contains statistics from component sync
 type ComponentSyncResult struct {
 	TotalSynced int
@@ -196,6 +203,44 @@ func (l *LocalDB) SearchLocalComponentsByCategory(category string, query string,
 	return components, err
 }
 
+// ListComponents returns components with filtering and pagination
+func (l *LocalDB) ListComponents(filter ComponentFilter, offset, limit int) ([]LocalComponent, int64, error) {
+	db := l.db
+
+	// Apply category filter
+	if filter.Category != "" {
+		db = db.Where("LOWER(category) = ?", strings.ToLower(filter.Category))
+	}
+
+	// Apply search filter
+	if filter.Search != "" {
+		searchPattern := "%" + strings.ToLower(filter.Search) + "%"
+		db = db.Where(
+			"LOWER(lot_name) LIKE ? OR LOWER(lot_description) LIKE ? OR LOWER(category) LIKE ? OR LOWER(model) LIKE ?",
+			searchPattern, searchPattern, searchPattern, searchPattern,
+		)
+	}
+
+	// Apply price filter
+	if filter.HasPrice {
+		db = db.Where("current_price IS NOT NULL")
+	}
+
+	// Get total count
+	var total int64
+	if err := db.Model(&LocalComponent{}).Count(&total).Error; err != nil {
+		return nil, 0, err
+	}
+
+	// Apply pagination and get results
+	var components []LocalComponent
+	if err := db.Order("lot_name").Offset(offset).Limit(limit).Find(&components).Error; err != nil {
+		return nil, 0, err
+	}
+
+	return components, total, nil
+}
+
 // GetLocalComponent returns a single component by lot_name
 func (l *LocalDB) GetLocalComponent(lotName string) (*LocalComponent, error) {
 	var component LocalComponent
@@ -266,3 +311,100 @@ func (l *LocalDB) NeedComponentSync(maxAgeHours int) bool {
 	}
 	return time.Since(*syncTime).Hours() > float64(maxAgeHours)
 }
+
+// UpdateComponentPricesFromPricelist updates current_price in local_components from pricelist items
+// This allows offline price updates using synced pricelists without MariaDB connection
+func (l *LocalDB) UpdateComponentPricesFromPricelist(pricelistID uint) (int, error) {
+	// Get all items from the specified pricelist
+	var items []LocalPricelistItem
+	if err := l.db.Where("pricelist_id = ?", pricelistID).Find(&items).Error; err != nil {
+		return 0, fmt.Errorf("fetching pricelist items: %w", err)
+	}
+
+	if len(items) == 0 {
+		slog.Warn("no items found in pricelist", "pricelist_id", pricelistID)
+		return 0, nil
+	}
+
+	// Update current_price for each component
+	updated := 0
+	err := l.db.Transaction(func(tx *gorm.DB) error {
+		for _, item := range items {
+			result := tx.Model(&LocalComponent{}).
+				Where("lot_name = ?", item.LotName).
+				Update("current_price", item.Price)
+
+			if result.Error != nil {
+				return fmt.Errorf("updating price for %s: %w", item.LotName, result.Error)
+			}
+
+			if result.RowsAffected > 0 {
+				updated++
+			}
+		}
+		return nil
+	})
+
+	if err != nil {
+		return 0, err
+	}
+
+	slog.Info("updated component prices from pricelist",
+		"pricelist_id", pricelistID,
+		"total_items", len(items),
+		"updated_components", updated)
+
+	return updated, nil
+}
+
+// EnsureComponentPricesFromPricelists loads prices from the latest pricelist into local_components
+// if no components exist or all current prices are NULL
+func (l *LocalDB) EnsureComponentPricesFromPricelists() error {
+	// Check if we have any components with prices
+	var count int64
+	if err := l.db.Model(&LocalComponent{}).Where("current_price IS NOT NULL").Count(&count).Error; err != nil {
+		return fmt.Errorf("checking component prices: %w", err)
+	}
+
+	// If we have components with prices, don't load from pricelists
+	if count > 0 {
+		return nil
+	}
+
+	// Check if we have any components at all
+	var totalComponents int64
+	if err := l.db.Model(&LocalComponent{}).Count(&totalComponents).Error; err != nil {
+		return fmt.Errorf("counting components: %w", err)
+	}
+
+	// If we have no components, we need to load them from pricelists
+	if totalComponents == 0 {
+		slog.Info("no components found in local database, loading from latest pricelist")
+		// This would typically be called from the sync service or setup process
+		// For now, we'll just return nil to indicate no action needed
+		return nil
+	}
+
+	// If we have components but no prices, we should load prices from pricelists
+	// Find the latest pricelist
+	var latestPricelist LocalPricelist
+	if err := l.db.Order("created_at DESC").First(&latestPricelist).Error; err != nil {
+		if err == gorm.ErrRecordNotFound {
+			slog.Warn("no pricelists found in local database")
+			return nil
+		}
+		return fmt.Errorf("finding latest pricelist: %w", err)
+	}
+
+	// Update prices from the latest pricelist
+	updated, err := l.UpdateComponentPricesFromPricelist(latestPricelist.ID)
+	if err != nil {
+		return fmt.Errorf("updating component prices from pricelist: %w", err)
+	}
+
+	slog.Info("loaded component prices from latest pricelist",
+		"pricelist_id", latestPricelist.ID,
+		"updated_components", updated)
+
+	return nil
+}