feat: implement vendor spec BOM import and PN→LOT resolution (Phase 1)

- Migration 029: local_partnumber_books, local_partnumber_book_items,
  vendor_spec TEXT column on local_configurations
- Models: LocalPartnumberBook, LocalPartnumberBookItem, VendorSpec,
  VendorSpecItem with JSON Valuer/Scanner
- Repository: PartnumberBookRepository (GetActiveBook, FindLotByPartnumber,
  SaveBook/Items, ListBooks, CountBookItems)
- Service: VendorSpecResolver 3-step resolution (book → manual suggestion
  → unresolved) + AggregateLOTs with is_primary_pn qty logic
- Sync: PullPartnumberBooks append-only pull from qt_partnumber_books
- Handlers: VendorSpecHandler (GET/PUT/resolve/apply), PartnumberBooksHandler
- Routes: /api/configs/:uuid/vendor-spec*, /api/partnumber-books,
  /api/sync/partnumber-books, /partnumber-books page
- UI: 3 top-level tabs [Estimate][BOM вендора][Ценообразование]; Excel paste,
  PN resolution, inline LOT autocomplete, pricing table
- Bible: 03-database.md updated, 09-vendor-spec.md added

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

internal/handlers/partnumber_books.go

@@ -0,0 +1,90 @@
+package handlers
+
+import (
+	"net/http"
+	"strconv"
+
+	"git.mchus.pro/mchus/quoteforge/internal/localdb"
+	"git.mchus.pro/mchus/quoteforge/internal/repository"
+	"github.com/gin-gonic/gin"
+)
+
+// PartnumberBooksHandler provides read-only access to local partnumber book snapshots.
+type PartnumberBooksHandler struct {
+	localDB *localdb.LocalDB
+}
+
+func NewPartnumberBooksHandler(localDB *localdb.LocalDB) *PartnumberBooksHandler {
+	return &PartnumberBooksHandler{localDB: localDB}
+}
+
+// List returns all local partnumber book snapshots.
+// GET /api/partnumber-books
+func (h *PartnumberBooksHandler) List(c *gin.Context) {
+	bookRepo := repository.NewPartnumberBookRepository(h.localDB.DB())
+	books, err := bookRepo.ListBooks()
+	if err != nil {
+		c.JSON(http.StatusInternalServerError, gin.H{"error": err.Error()})
+		return
+	}
+
+	type bookSummary struct {
+		ID        uint   `json:"id"`
+		ServerID  int    `json:"server_id"`
+		Version   string `json:"version"`
+		CreatedAt string `json:"created_at"`
+		IsActive  bool   `json:"is_active"`
+		ItemCount int64  `json:"item_count"`
+	}
+
+	summaries := make([]bookSummary, 0, len(books))
+	for _, b := range books {
+		summaries = append(summaries, bookSummary{
+			ID:        b.ID,
+			ServerID:  b.ServerID,
+			Version:   b.Version,
+			CreatedAt: b.CreatedAt.Format("2006-01-02"),
+			IsActive:  b.IsActive,
+			ItemCount: bookRepo.CountBookItems(b.ID),
+		})
+	}
+
+	c.JSON(http.StatusOK, gin.H{
+		"books": summaries,
+		"total": len(summaries),
+	})
+}
+
+// GetItems returns items for a partnumber book by server ID.
+// GET /api/partnumber-books/:id
+func (h *PartnumberBooksHandler) GetItems(c *gin.Context) {
+	idStr := c.Param("id")
+	id, err := strconv.ParseUint(idStr, 10, 64)
+	if err != nil {
+		c.JSON(http.StatusBadRequest, gin.H{"error": "invalid book ID"})
+		return
+	}
+
+	bookRepo := repository.NewPartnumberBookRepository(h.localDB.DB())
+
+	// Find local book by server_id
+	var book localdb.LocalPartnumberBook
+	if err := h.localDB.DB().Where("server_id = ?", id).First(&book).Error; err != nil {
+		c.JSON(http.StatusNotFound, gin.H{"error": "partnumber book not found"})
+		return
+	}
+
+	items, err := bookRepo.GetBookItems(book.ID)
+	if err != nil {
+		c.JSON(http.StatusInternalServerError, gin.H{"error": err.Error()})
+		return
+	}
+
+	c.JSON(http.StatusOK, gin.H{
+		"book_id":   book.ServerID,
+		"version":   book.Version,
+		"is_active": book.IsActive,
+		"items":     items,
+		"total":     len(items),
+	})
+}

internal/handlers/sync.go

@@ -243,6 +243,33 @@ func (h *SyncHandler) SyncPricelists(c *gin.Context) {
 	h.syncService.RecordSyncHeartbeat()
 }
 
+// SyncPartnumberBooks syncs partnumber book snapshots from MariaDB to local SQLite.
+// POST /api/sync/partnumber-books
+func (h *SyncHandler) SyncPartnumberBooks(c *gin.Context) {
+	if !h.ensureSyncReadiness(c) {
+		return
+	}
+
+	startTime := time.Now()
+	pulled, err := h.syncService.PullPartnumberBooks()
+	if err != nil {
+		slog.Error("partnumber books pull failed", "error", err)
+		c.JSON(http.StatusInternalServerError, gin.H{
+			"success": false,
+			"error":   err.Error(),
+		})
+		return
+	}
+
+	c.JSON(http.StatusOK, SyncResultResponse{
+		Success:  true,
+		Message:  "Partnumber books synced successfully",
+		Synced:   pulled,
+		Duration: time.Since(startTime).String(),
+	})
+	h.syncService.RecordSyncHeartbeat()
+}
+
 // SyncAllResponse represents result of full sync
 type SyncAllResponse struct {
 	Success                bool   `json:"success"`

internal/handlers/vendor_spec.go

@@ -0,0 +1,166 @@
+package handlers
+
+import (
+	"encoding/json"
+	"net/http"
+
+	"git.mchus.pro/mchus/quoteforge/internal/localdb"
+	"git.mchus.pro/mchus/quoteforge/internal/middleware"
+	"git.mchus.pro/mchus/quoteforge/internal/repository"
+	"git.mchus.pro/mchus/quoteforge/internal/services"
+	"github.com/gin-gonic/gin"
+)
+
+// VendorSpecHandler handles vendor BOM spec operations for a configuration.
+type VendorSpecHandler struct {
+	localDB *localdb.LocalDB
+}
+
+func NewVendorSpecHandler(localDB *localdb.LocalDB) *VendorSpecHandler {
+	return &VendorSpecHandler{localDB: localDB}
+}
+
+// GetVendorSpec returns the vendor spec (BOM) for a configuration.
+// GET /api/configs/:uuid/vendor-spec
+func (h *VendorSpecHandler) GetVendorSpec(c *gin.Context) {
+	uuid := c.Param("uuid")
+	username := middleware.GetUsername(c)
+
+	var cfg localdb.LocalConfiguration
+	if err := h.localDB.DB().Where("uuid = ? AND original_username = ? AND is_active = 1", uuid, username).First(&cfg).Error; err != nil {
+		c.JSON(http.StatusNotFound, gin.H{"error": "configuration not found"})
+		return
+	}
+
+	spec := cfg.VendorSpec
+	if spec == nil {
+		spec = localdb.VendorSpec{}
+	}
+	c.JSON(http.StatusOK, gin.H{"vendor_spec": spec})
+}
+
+// PutVendorSpec saves (replaces) the vendor spec for a configuration.
+// PUT /api/configs/:uuid/vendor-spec
+func (h *VendorSpecHandler) PutVendorSpec(c *gin.Context) {
+	uuid := c.Param("uuid")
+	username := middleware.GetUsername(c)
+
+	var body struct {
+		VendorSpec []localdb.VendorSpecItem `json:"vendor_spec"`
+	}
+	if err := c.ShouldBindJSON(&body); err != nil {
+		c.JSON(http.StatusBadRequest, gin.H{"error": err.Error()})
+		return
+	}
+
+	var cfg localdb.LocalConfiguration
+	if err := h.localDB.DB().Where("uuid = ? AND original_username = ? AND is_active = 1", uuid, username).First(&cfg).Error; err != nil {
+		c.JSON(http.StatusNotFound, gin.H{"error": "configuration not found"})
+		return
+	}
+
+	// Assign sort_order if not set
+	for i := range body.VendorSpec {
+		if body.VendorSpec[i].SortOrder == 0 {
+			body.VendorSpec[i].SortOrder = (i + 1) * 10
+		}
+	}
+
+	spec := localdb.VendorSpec(body.VendorSpec)
+	if err := h.localDB.DB().Model(&cfg).Update("vendor_spec", spec).Error; err != nil {
+		c.JSON(http.StatusInternalServerError, gin.H{"error": err.Error()})
+		return
+	}
+
+	c.JSON(http.StatusOK, gin.H{"vendor_spec": spec})
+}
+
+// ResolveVendorSpec resolves vendor PN → LOT without modifying the cart.
+// POST /api/configs/:uuid/vendor-spec/resolve
+func (h *VendorSpecHandler) ResolveVendorSpec(c *gin.Context) {
+	uuid := c.Param("uuid")
+	username := middleware.GetUsername(c)
+
+	var cfg localdb.LocalConfiguration
+	if err := h.localDB.DB().Where("uuid = ? AND original_username = ? AND is_active = 1", uuid, username).First(&cfg).Error; err != nil {
+		c.JSON(http.StatusNotFound, gin.H{"error": "configuration not found"})
+		return
+	}
+
+	var body struct {
+		VendorSpec []localdb.VendorSpecItem `json:"vendor_spec"`
+	}
+	if err := c.ShouldBindJSON(&body); err != nil {
+		c.JSON(http.StatusBadRequest, gin.H{"error": err.Error()})
+		return
+	}
+
+	bookRepo := repository.NewPartnumberBookRepository(h.localDB.DB())
+	resolver := services.NewVendorSpecResolver(bookRepo)
+
+	resolved, err := resolver.Resolve(body.VendorSpec)
+	if err != nil {
+		c.JSON(http.StatusInternalServerError, gin.H{"error": err.Error()})
+		return
+	}
+
+	// Also compute aggregated LOTs
+	book, _ := bookRepo.GetActiveBook()
+	aggregated, err := services.AggregateLOTs(resolved, book, bookRepo)
+	if err != nil {
+		c.JSON(http.StatusInternalServerError, gin.H{"error": err.Error()})
+		return
+	}
+
+	c.JSON(http.StatusOK, gin.H{
+		"resolved":   resolved,
+		"aggregated": aggregated,
+	})
+}
+
+// ApplyVendorSpec applies the resolved BOM to the cart (Estimate items).
+// POST /api/configs/:uuid/vendor-spec/apply
+func (h *VendorSpecHandler) ApplyVendorSpec(c *gin.Context) {
+	uuid := c.Param("uuid")
+	username := middleware.GetUsername(c)
+
+	var body struct {
+		Items []struct {
+			LotName   string  `json:"lot_name"`
+			Quantity  int     `json:"quantity"`
+			UnitPrice float64 `json:"unit_price"`
+		} `json:"items"`
+	}
+	if err := c.ShouldBindJSON(&body); err != nil {
+		c.JSON(http.StatusBadRequest, gin.H{"error": err.Error()})
+		return
+	}
+
+	var cfg localdb.LocalConfiguration
+	if err := h.localDB.DB().Where("uuid = ? AND original_username = ? AND is_active = 1", uuid, username).First(&cfg).Error; err != nil {
+		c.JSON(http.StatusNotFound, gin.H{"error": "configuration not found"})
+		return
+	}
+
+	newItems := make(localdb.LocalConfigItems, 0, len(body.Items))
+	for _, it := range body.Items {
+		newItems = append(newItems, localdb.LocalConfigItem{
+			LotName:   it.LotName,
+			Quantity:  it.Quantity,
+			UnitPrice: it.UnitPrice,
+		})
+	}
+
+	itemsJSON, err := json.Marshal(newItems)
+	if err != nil {
+		c.JSON(http.StatusInternalServerError, gin.H{"error": err.Error()})
+		return
+	}
+
+	if err := h.localDB.DB().Model(&cfg).Update("items", string(itemsJSON)).Error; err != nil {
+		c.JSON(http.StatusInternalServerError, gin.H{"error": err.Error()})
+		return
+	}
+
+	c.JSON(http.StatusOK, gin.H{"items": newItems})
+}

internal/handlers/web.go

@@ -67,7 +67,7 @@ func NewWebHandler(templatesPath string, componentService *services.ComponentSer
 	}
 
 	// Load each page template with base
-	simplePages := []string{"login.html", "configs.html", "projects.html", "project_detail.html", "pricelists.html", "pricelist_detail.html", "config_revisions.html"}
+	simplePages := []string{"login.html", "configs.html", "projects.html", "project_detail.html", "pricelists.html", "pricelist_detail.html", "config_revisions.html", "partnumber_books.html"}
 	for _, page := range simplePages {
 		pagePath := filepath.Join(templatesPath, page)
 		var tmpl *template.Template
@@ -212,6 +212,10 @@ func (h *WebHandler) PricelistDetail(c *gin.Context) {
 	h.render(c, "pricelist_detail.html", gin.H{"ActivePage": "pricelists"})
 }
 
+func (h *WebHandler) PartnumberBooks(c *gin.Context) {
+	h.render(c, "partnumber_books.html", gin.H{"ActivePage": "partnumber-books"})
+}
+
 // Partials for htmx
 
 func (h *WebHandler) ComponentsPartial(c *gin.Context) {

internal/localdb/models.go

@@ -103,6 +103,7 @@ type LocalConfiguration struct {
 	WarehousePricelistID  *uint                       `gorm:"index" json:"warehouse_pricelist_id,omitempty"`
 	CompetitorPricelistID *uint                       `gorm:"index" json:"competitor_pricelist_id,omitempty"`
 	OnlyInStock           bool                        `gorm:"default:false" json:"only_in_stock"`
+	VendorSpec             VendorSpec                  `gorm:"type:text" json:"vendor_spec,omitempty"`
 	Line                  int                         `gorm:"column:line_no;index" json:"line"`
 	PriceUpdatedAt        *time.Time                  `gorm:"type:timestamp" json:"price_updated_at,omitempty"`
 	CreatedAt             time.Time                   `json:"created_at"`
@@ -243,3 +244,70 @@ type PendingChange struct {
 func (PendingChange) TableName() string {
 	return "pending_changes"
 }
+
+// LocalPartnumberBook stores a version snapshot of the PN→LOT mapping book (pull-only from PriceForge)
+type LocalPartnumberBook struct {
+	ID        uint      `gorm:"primaryKey;autoIncrement" json:"id"`
+	ServerID  int       `gorm:"uniqueIndex;not null" json:"server_id"`
+	Version   string    `gorm:"not null" json:"version"`
+	CreatedAt time.Time `gorm:"not null" json:"created_at"`
+	IsActive  bool      `gorm:"not null;default:true" json:"is_active"`
+}
+
+func (LocalPartnumberBook) TableName() string {
+	return "local_partnumber_books"
+}
+
+// LocalPartnumberBookItem stores a single PN→LOT mapping within a book snapshot
+type LocalPartnumberBookItem struct {
+	ID          uint   `gorm:"primaryKey;autoIncrement" json:"id"`
+	BookID      uint   `gorm:"not null;index:idx_local_book_pn,priority:1" json:"book_id"`
+	Partnumber  string `gorm:"not null;index:idx_local_book_pn,priority:2" json:"partnumber"`
+	LotName     string `gorm:"not null" json:"lot_name"`
+	IsPrimaryPN bool   `gorm:"not null;default:false" json:"is_primary_pn"`
+	Description string `json:"description,omitempty"`
+}
+
+func (LocalPartnumberBookItem) TableName() string {
+	return "local_partnumber_book_items"
+}
+
+// VendorSpecItem represents a single row in a vendor BOM specification
+type VendorSpecItem struct {
+	SortOrder           int      `json:"sort_order"`
+	VendorPartnumber    string   `json:"vendor_partnumber"`
+	Quantity            int      `json:"quantity"`
+	Description         string   `json:"description,omitempty"`
+	UnitPrice           *float64 `json:"unit_price,omitempty"`
+	TotalPrice          *float64 `json:"total_price,omitempty"`
+	ResolvedLotName     string   `json:"resolved_lot_name,omitempty"`
+	ResolutionSource    string   `json:"resolution_source,omitempty"` // "book", "manual", "unresolved"
+	ManualLotSuggestion string   `json:"manual_lot_suggestion,omitempty"`
+}
+
+// VendorSpec is a JSON-encodable slice of VendorSpecItem
+type VendorSpec []VendorSpecItem
+
+func (v VendorSpec) Value() (driver.Value, error) {
+	if v == nil {
+		return nil, nil
+	}
+	return json.Marshal(v)
+}
+
+func (v *VendorSpec) Scan(value interface{}) error {
+	if value == nil {
+		*v = nil
+		return nil
+	}
+	var bytes []byte
+	switch val := value.(type) {
+	case []byte:
+		bytes = val
+	case string:
+		bytes = []byte(val)
+	default:
+		return errors.New("type assertion failed for VendorSpec")
+	}
+	return json.Unmarshal(bytes, v)
+}

internal/repository/partnumber_book.go

@@ -0,0 +1,66 @@
+package repository
+
+import (
+	"git.mchus.pro/mchus/quoteforge/internal/localdb"
+	"gorm.io/gorm"
+)
+
+// PartnumberBookRepository provides read-only access to local partnumber book snapshots.
+type PartnumberBookRepository struct {
+	db *gorm.DB
+}
+
+func NewPartnumberBookRepository(db *gorm.DB) *PartnumberBookRepository {
+	return &PartnumberBookRepository{db: db}
+}
+
+// GetActiveBook returns the most recently active local partnumber book.
+func (r *PartnumberBookRepository) GetActiveBook() (*localdb.LocalPartnumberBook, error) {
+	var book localdb.LocalPartnumberBook
+	err := r.db.Where("is_active = 1").Order("created_at DESC, id DESC").First(&book).Error
+	if err != nil {
+		return nil, err
+	}
+	return &book, nil
+}
+
+// GetBookItems returns all items for the given local book ID.
+func (r *PartnumberBookRepository) GetBookItems(bookID uint) ([]localdb.LocalPartnumberBookItem, error) {
+	var items []localdb.LocalPartnumberBookItem
+	err := r.db.Where("book_id = ?", bookID).Find(&items).Error
+	return items, err
+}
+
+// FindLotByPartnumber looks up a partnumber in the active book and returns the matching items.
+func (r *PartnumberBookRepository) FindLotByPartnumber(bookID uint, partnumber string) ([]localdb.LocalPartnumberBookItem, error) {
+	var items []localdb.LocalPartnumberBookItem
+	err := r.db.Where("book_id = ? AND partnumber = ?", bookID, partnumber).Find(&items).Error
+	return items, err
+}
+
+// ListBooks returns all local partnumber books ordered newest first.
+func (r *PartnumberBookRepository) ListBooks() ([]localdb.LocalPartnumberBook, error) {
+	var books []localdb.LocalPartnumberBook
+	err := r.db.Order("created_at DESC, id DESC").Find(&books).Error
+	return books, err
+}
+
+// SaveBook saves a new partnumber book snapshot.
+func (r *PartnumberBookRepository) SaveBook(book *localdb.LocalPartnumberBook) error {
+	return r.db.Save(book).Error
+}
+
+// SaveBookItems bulk-inserts items for a book snapshot.
+func (r *PartnumberBookRepository) SaveBookItems(items []localdb.LocalPartnumberBookItem) error {
+	if len(items) == 0 {
+		return nil
+	}
+	return r.db.CreateInBatches(items, 500).Error
+}
+
+// CountBookItems returns the number of items for a given local book ID.
+func (r *PartnumberBookRepository) CountBookItems(bookID uint) int64 {
+	var count int64
+	r.db.Model(&localdb.LocalPartnumberBookItem{}).Where("book_id = ?", bookID).Count(&count)
+	return count
+}

internal/services/sync/partnumber_books.go

@@ -0,0 +1,92 @@
+package sync
+
+import (
+	"fmt"
+	"log/slog"
+	"time"
+
+	"git.mchus.pro/mchus/quoteforge/internal/localdb"
+	"git.mchus.pro/mchus/quoteforge/internal/repository"
+)
+
+// PullPartnumberBooks synchronizes partnumber book snapshots from MariaDB to local SQLite.
+// It only pulls books that don't exist locally yet (append-only).
+func (s *Service) PullPartnumberBooks() (int, error) {
+	slog.Info("starting partnumber book pull")
+
+	mariaDB, err := s.getDB()
+	if err != nil {
+		return 0, fmt.Errorf("database not available: %w", err)
+	}
+
+	localBookRepo := repository.NewPartnumberBookRepository(s.localDB.DB())
+
+	// Query server for all active partnumber books
+	type serverBook struct {
+		ID        int       `gorm:"column:id"`
+		Version   string    `gorm:"column:version"`
+		CreatedAt time.Time `gorm:"column:created_at"`
+		IsActive  bool      `gorm:"column:is_active"`
+	}
+	var serverBooks []serverBook
+	if err := mariaDB.Raw("SELECT id, version, created_at, is_active FROM qt_partnumber_books WHERE is_active = 1 ORDER BY created_at DESC, id DESC").Scan(&serverBooks).Error; err != nil {
+		return 0, fmt.Errorf("querying server partnumber books: %w", err)
+	}
+
+	pulled := 0
+	for _, sb := range serverBooks {
+		// Check if already exists locally
+		var existing localdb.LocalPartnumberBook
+		err := s.localDB.DB().Where("server_id = ?", sb.ID).First(&existing).Error
+		if err == nil {
+			// Already exists
+			continue
+		}
+
+		// Save the book
+		localBook := &localdb.LocalPartnumberBook{
+			ServerID:  sb.ID,
+			Version:   sb.Version,
+			CreatedAt: sb.CreatedAt,
+			IsActive:  sb.IsActive,
+		}
+		if err := localBookRepo.SaveBook(localBook); err != nil {
+			slog.Warn("failed to save local partnumber book", "server_id", sb.ID, "error", err)
+			continue
+		}
+
+		// Pull items for this book
+		type serverItem struct {
+			Partnumber  string `gorm:"column:partnumber"`
+			LotName     string `gorm:"column:lot_name"`
+			IsPrimaryPN bool   `gorm:"column:is_primary_pn"`
+			Description string `gorm:"column:description"`
+		}
+		var serverItems []serverItem
+		if err := mariaDB.Raw("SELECT partnumber, lot_name, is_primary_pn, description FROM qt_partnumber_book_items WHERE book_id = ?", sb.ID).Scan(&serverItems).Error; err != nil {
+			slog.Warn("failed to query server partnumber book items", "book_id", sb.ID, "error", err)
+			continue
+		}
+
+		localItems := make([]localdb.LocalPartnumberBookItem, 0, len(serverItems))
+		for _, si := range serverItems {
+			localItems = append(localItems, localdb.LocalPartnumberBookItem{
+				BookID:      localBook.ID,
+				Partnumber:  si.Partnumber,
+				LotName:     si.LotName,
+				IsPrimaryPN: si.IsPrimaryPN,
+				Description: si.Description,
+			})
+		}
+		if err := localBookRepo.SaveBookItems(localItems); err != nil {
+			slog.Warn("failed to save local partnumber book items", "book_id", localBook.ID, "error", err)
+			continue
+		}
+
+		slog.Info("pulled partnumber book", "version", sb.Version, "items", len(localItems))
+		pulled++
+	}
+
+	slog.Info("partnumber book pull completed", "pulled", pulled)
+	return pulled, nil
+}

internal/services/vendor_spec_resolver.go

@@ -0,0 +1,129 @@
+package services
+
+import (
+	"git.mchus.pro/mchus/quoteforge/internal/localdb"
+	"git.mchus.pro/mchus/quoteforge/internal/repository"
+)
+
+// ResolvedBOMRow is the result of resolving a single vendor BOM row.
+type ResolvedBOMRow struct {
+	localdb.VendorSpecItem
+	// ResolutionSource already on VendorSpecItem: "book", "manual_suggestion", "unresolved"
+}
+
+// AggregatedLOT represents a LOT with its aggregated quantity from the BOM.
+type AggregatedLOT struct {
+	LotName  string
+	Quantity int
+}
+
+// VendorSpecResolver resolves vendor BOM rows to LOT names using the active partnumber book.
+type VendorSpecResolver struct {
+	bookRepo *repository.PartnumberBookRepository
+}
+
+func NewVendorSpecResolver(bookRepo *repository.PartnumberBookRepository) *VendorSpecResolver {
+	return &VendorSpecResolver{bookRepo: bookRepo}
+}
+
+// Resolve resolves each vendor spec item's lot name using the 3-step algorithm.
+// It returns the resolved items. Manual lot suggestions from the input are preserved as pre-fill.
+func (r *VendorSpecResolver) Resolve(items []localdb.VendorSpecItem) ([]localdb.VendorSpecItem, error) {
+	// Step 1: Get the active book
+	book, err := r.bookRepo.GetActiveBook()
+	if err != nil {
+		// No book available — mark all as unresolved
+		for i := range items {
+			if items[i].ResolvedLotName == "" {
+				items[i].ResolutionSource = "unresolved"
+			}
+		}
+		return items, nil
+	}
+
+	for i, item := range items {
+		pn := item.VendorPartnumber
+
+		// Step 1: Look up in active book
+		matches, err := r.bookRepo.FindLotByPartnumber(book.ID, pn)
+		if err == nil && len(matches) > 0 {
+			items[i].ResolvedLotName = matches[0].LotName
+			items[i].ResolutionSource = "book"
+			continue
+		}
+
+		// Step 2: Pre-fill from manual_lot_suggestion if provided
+		if item.ManualLotSuggestion != "" {
+			items[i].ResolvedLotName = item.ManualLotSuggestion
+			items[i].ResolutionSource = "manual_suggestion"
+			continue
+		}
+
+		// Step 3: Unresolved
+		items[i].ResolvedLotName = ""
+		items[i].ResolutionSource = "unresolved"
+	}
+
+	return items, nil
+}
+
+// AggregateLOTs applies the qty-logic to compute per-LOT quantities from the resolved BOM.
+// qty(lot) = SUM(qty of primary PN rows for this lot) if any primary PN exists, else 1.
+func AggregateLOTs(items []localdb.VendorSpecItem, book *localdb.LocalPartnumberBook, bookRepo *repository.PartnumberBookRepository) ([]AggregatedLOT, error) {
+	// Gather all unique lot names that resolved
+	lotPrimary := make(map[string]int)     // lot_name → sum of primary PN quantities
+	lotAny := make(map[string]bool)        // lot_name → seen at least once (non-primary)
+	lotHasPrimary := make(map[string]bool) // lot_name → has at least one primary PN in spec
+
+	if book != nil {
+		for _, item := range items {
+			if item.ResolvedLotName == "" {
+				continue
+			}
+			lot := item.ResolvedLotName
+			pn := item.VendorPartnumber
+
+			// Find if this pn is primary for its lot
+			matches, err := bookRepo.FindLotByPartnumber(book.ID, pn)
+			if err != nil || len(matches) == 0 {
+				// manual/unresolved — treat as non-primary
+				lotAny[lot] = true
+				continue
+			}
+			for _, m := range matches {
+				if m.LotName == lot {
+					if m.IsPrimaryPN {
+						lotPrimary[lot] += item.Quantity
+						lotHasPrimary[lot] = true
+					} else {
+						lotAny[lot] = true
+					}
+				}
+			}
+		}
+	} else {
+		// No book: all resolved rows contribute qty=1 per lot
+		for _, item := range items {
+			if item.ResolvedLotName != "" {
+				lotAny[item.ResolvedLotName] = true
+			}
+		}
+	}
+
+	// Build aggregated list
+	seen := make(map[string]bool)
+	var result []AggregatedLOT
+	for _, item := range items {
+		lot := item.ResolvedLotName
+		if lot == "" || seen[lot] {
+			continue
+		}
+		seen[lot] = true
+		qty := 1
+		if lotHasPrimary[lot] {
+			qty = lotPrimary[lot]
+		}
+		result = append(result, AggregatedLOT{LotName: lot, Quantity: qty})
+	}
+	return result, nil
+}