feat: add pricelist CSV export and improve description display

- Add CSV export functionality for pricelists with download button
- Export includes all pricelist items with proper UTF-8 encoding
- Support both warehouse and estimate pricelist sources
- Remove description column from admin pricing tables
- Show description as tooltip on row hover instead
- Improve table layout by removing redundant column

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

internal/handlers/pricelist.go

@@ -1,7 +1,9 @@
 package handlers
 
 import (
+	"encoding/csv"
 	"errors"
+	"fmt"
 	"io"
 	"net/http"
 	"strconv"
@@ -239,3 +241,160 @@ func (h *PricelistHandler) GetLatest(c *gin.Context) {
 	}
 	c.JSON(http.StatusOK, pl)
 }
+
+func (h *PricelistHandler) ExportCSV(c *gin.Context) {
+	id, err := strconv.ParseUint(c.Param("id"), 10, 32)
+	if err != nil {
+		c.JSON(http.StatusBadRequest, gin.H{"error": "invalid pricelist ID"})
+		return
+	}
+
+	// Get pricelist info
+	pl, err := h.service.GetByID(uint(id))
+	if err != nil {
+		c.JSON(http.StatusNotFound, gin.H{"error": "pricelist not found"})
+		return
+	}
+
+	// Get all items (no pagination)
+	items, _, err := h.service.GetItems(uint(id), 1, 999999, "")
+	if err != nil {
+		c.JSON(http.StatusInternalServerError, gin.H{"error": err.Error()})
+		return
+	}
+
+	// Set response headers for CSV download
+	filename := fmt.Sprintf("pricelist_%s.csv", pl.Version)
+	c.Header("Content-Type", "text/csv; charset=utf-8")
+	c.Header("Content-Disposition", fmt.Sprintf("attachment; filename=\"%s\"", filename))
+
+	// Create CSV writer
+	writer := csv.NewWriter(c.Writer)
+	defer writer.Flush()
+
+	// Write UTF-8 BOM for Excel compatibility
+	c.Writer.Write([]byte{0xEF, 0xBB, 0xBF})
+
+	// Determine if warehouse source
+	isWarehouse := strings.ToLower(pl.Source) == "warehouse"
+
+	// Write CSV header
+	var header []string
+	if isWarehouse {
+		header = []string{"Артикул", "Категория", "Описание", "Доступно", "Partnumbers", "Цена, $", "Настройки"}
+	} else {
+		header = []string{"Артикул", "Категория", "Описание", "Цена, $", "Настройки"}
+	}
+	if err := writer.Write(header); err != nil {
+		c.JSON(http.StatusInternalServerError, gin.H{"error": "failed to write CSV header"})
+		return
+	}
+
+	// Write items
+	for _, item := range items {
+		row := make([]string, 0, len(header))
+
+		// Артикул
+		row = append(row, item.LotName)
+
+		// Категория
+		category := item.Category
+		if category == "" {
+			category = "-"
+		}
+		row = append(row, category)
+
+		// Описание
+		description := item.LotDescription
+		if description == "" {
+			description = "-"
+		}
+		row = append(row, description)
+
+		if isWarehouse {
+			// Доступно
+			qty := "-"
+			if item.AvailableQty != nil {
+				qty = fmt.Sprintf("%.3f", *item.AvailableQty)
+			}
+			row = append(row, qty)
+
+			// Partnumbers
+			partnumbers := "-"
+			if len(item.Partnumbers) > 0 {
+				partnumbers = strings.Join(item.Partnumbers, ", ")
+			}
+			row = append(row, partnumbers)
+		}
+
+		// Цена
+		row = append(row, fmt.Sprintf("%.2f", item.Price))
+
+		// Настройки
+		settings := formatPriceSettings(item)
+		row = append(row, settings)
+
+		if err := writer.Write(row); err != nil {
+			c.JSON(http.StatusInternalServerError, gin.H{"error": "failed to write CSV row"})
+			return
+		}
+	}
+}
+
+func formatPriceSettings(item models.PricelistItem) string {
+	var settings []string
+
+	hasManualPrice := item.ManualPrice != nil && *item.ManualPrice > 0
+	hasMeta := item.MetaPrices != ""
+	method := strings.ToLower(item.PriceMethod)
+
+	// Method indicator
+	if hasManualPrice {
+		settings = append(settings, "РУЧН")
+	} else if method == "average" {
+		settings = append(settings, "Сред")
+	} else if method == "weighted_median" {
+		settings = append(settings, "Взвеш. мед")
+	} else {
+		settings = append(settings, "Мед")
+	}
+
+	// Period (only if not manual price)
+	if !hasManualPrice {
+		period := item.PricePeriodDays
+		switch period {
+		case 7:
+			settings = append(settings, "1н")
+		case 30:
+			settings = append(settings, "1м")
+		case 90:
+			settings = append(settings, "3м")
+		case 365:
+			settings = append(settings, "1г")
+		case 0:
+			settings = append(settings, "все")
+		default:
+			settings = append(settings, fmt.Sprintf("%dд", period))
+		}
+	}
+
+	// Coefficient
+	if item.PriceCoefficient != 0 {
+		coef := item.PriceCoefficient
+		if coef > 0 {
+			settings = append(settings, fmt.Sprintf("+%.0f%%", coef))
+		} else {
+			settings = append(settings, fmt.Sprintf("%.0f%%", coef))
+		}
+	}
+
+	// Meta article indicator
+	if hasMeta {
+		settings = append(settings, "МЕТА")
+	}
+
+	if len(settings) == 0 {
+		return "-"
+	}
+	return strings.Join(settings, " | ")
+}