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/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})
+}