Add Phase 2: Local SQLite database with sync functionality

Implements complete offline-first architecture with SQLite caching and MariaDB synchronization.

Key features:
- Local SQLite database for offline operation (data/quoteforge.db)
- Connection settings with encrypted credentials
- Component and pricelist caching with auto-sync
- Sync API endpoints (/api/sync/status, /components, /pricelists, /all)
- Real-time sync status indicator in UI with auto-refresh
- Offline mode detection middleware
- Migration tool for database initialization
- Setup wizard for initial configuration

New components:
- internal/localdb: SQLite repository layer (components, pricelists, sync)
- internal/services/sync: Synchronization service
- internal/handlers/sync: Sync API handlers
- internal/handlers/setup: Setup wizard handlers
- internal/middleware/offline: Offline detection
- cmd/migrate: Database migration tool

UI improvements:
- Setup page for database configuration
- Sync status indicator with online/offline detection
- Warning icons for pending synchronization
- Auto-refresh every 30 seconds

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

internal/services/configuration.go

@@ -194,6 +194,149 @@ func (s *ConfigurationService) ListByUser(userID uint, page, perPage int) ([]mod
 	return s.configRepo.ListByUser(userID, offset, perPage)
 }
 
+// ListAll returns all configurations without user filter (for use when auth is disabled)
+func (s *ConfigurationService) ListAll(page, perPage int) ([]models.Configuration, int64, error) {
+	if page < 1 {
+		page = 1
+	}
+	if perPage < 1 || perPage > 100 {
+		perPage = 20
+	}
+	offset := (page - 1) * perPage
+
+	return s.configRepo.ListAll(offset, perPage)
+}
+
+// GetByUUIDNoAuth returns configuration without ownership check (for use when auth is disabled)
+func (s *ConfigurationService) GetByUUIDNoAuth(uuid string) (*models.Configuration, error) {
+	config, err := s.configRepo.GetByUUID(uuid)
+	if err != nil {
+		return nil, ErrConfigNotFound
+	}
+	return config, nil
+}
+
+// UpdateNoAuth updates configuration without ownership check
+func (s *ConfigurationService) UpdateNoAuth(uuid string, req *CreateConfigRequest) (*models.Configuration, error) {
+	config, err := s.configRepo.GetByUUID(uuid)
+	if err != nil {
+		return nil, ErrConfigNotFound
+	}
+
+	total := req.Items.Total()
+	if req.ServerCount > 1 {
+		total *= float64(req.ServerCount)
+	}
+
+	config.Name = req.Name
+	config.Items = req.Items
+	config.TotalPrice = &total
+	config.CustomPrice = req.CustomPrice
+	config.Notes = req.Notes
+	config.IsTemplate = req.IsTemplate
+	config.ServerCount = req.ServerCount
+
+	if err := s.configRepo.Update(config); err != nil {
+		return nil, err
+	}
+
+	return config, nil
+}
+
+// DeleteNoAuth deletes configuration without ownership check
+func (s *ConfigurationService) DeleteNoAuth(uuid string) error {
+	config, err := s.configRepo.GetByUUID(uuid)
+	if err != nil {
+		return ErrConfigNotFound
+	}
+	return s.configRepo.Delete(config.ID)
+}
+
+// RenameNoAuth renames configuration without ownership check
+func (s *ConfigurationService) RenameNoAuth(uuid string, newName string) (*models.Configuration, error) {
+	config, err := s.configRepo.GetByUUID(uuid)
+	if err != nil {
+		return nil, ErrConfigNotFound
+	}
+
+	config.Name = newName
+	if err := s.configRepo.Update(config); err != nil {
+		return nil, err
+	}
+
+	return config, nil
+}
+
+// CloneNoAuth clones configuration without ownership check
+func (s *ConfigurationService) CloneNoAuth(configUUID string, newName string, userID uint) (*models.Configuration, error) {
+	original, err := s.configRepo.GetByUUID(configUUID)
+	if err != nil {
+		return nil, ErrConfigNotFound
+	}
+
+	total := original.Items.Total()
+	if original.ServerCount > 1 {
+		total *= float64(original.ServerCount)
+	}
+
+	clone := &models.Configuration{
+		UUID:        uuid.New().String(),
+		UserID:      userID, // Use provided user ID
+		Name:        newName,
+		Items:       original.Items,
+		TotalPrice:  &total,
+		CustomPrice: original.CustomPrice,
+		Notes:       original.Notes,
+		IsTemplate:  false,
+		ServerCount: original.ServerCount,
+	}
+
+	if err := s.configRepo.Create(clone); err != nil {
+		return nil, err
+	}
+
+	return clone, nil
+}
+
+// RefreshPricesNoAuth refreshes prices without ownership check
+func (s *ConfigurationService) RefreshPricesNoAuth(uuid string) (*models.Configuration, error) {
+	config, err := s.configRepo.GetByUUID(uuid)
+	if err != nil {
+		return nil, ErrConfigNotFound
+	}
+
+	updatedItems := make(models.ConfigItems, len(config.Items))
+	for i, item := range config.Items {
+		metadata, err := s.componentRepo.GetByLotName(item.LotName)
+		if err != nil || metadata.CurrentPrice == nil {
+			updatedItems[i] = item
+			continue
+		}
+
+		updatedItems[i] = models.ConfigItem{
+			LotName:   item.LotName,
+			Quantity:  item.Quantity,
+			UnitPrice: *metadata.CurrentPrice,
+		}
+	}
+
+	config.Items = updatedItems
+	total := updatedItems.Total()
+	if config.ServerCount > 1 {
+		total *= float64(config.ServerCount)
+	}
+
+	config.TotalPrice = &total
+	now := time.Now()
+	config.PriceUpdatedAt = &now
+
+	if err := s.configRepo.Update(config); err != nil {
+		return nil, err
+	}
+
+	return config, nil
+}
+
 func (s *ConfigurationService) ListTemplates(page, perPage int) ([]models.Configuration, int64, error) {
 	if page < 1 {
 		page = 1