feat(search): 库存搜索支持拼音/首字母，按回车触发

- 新增 util.ToPinyin()，使用 go-pinyin 生成全拼和首字母
- Product model 新增 name_pinyin / name_initials 列（AutoMigrate）
- 启动时自动回填存量商品拼音
- Create / Update / FindOrCreate 写入时同步生成拼音
- 库存搜索 SQL 加入拼音/首字母 LIKE 条件
- 前端去掉 300ms 防抖，改为回车/点击搜索按钮触发

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

backend/internal/handler/inventory.go

@@ -64,9 +64,9 @@ func (h *InventoryHandler) List(c *gin.Context) {
 	inStock := c.Query("in_stock")
 
 	if keyword != "" {
-		baseWhere += " AND (COALESCE(NULLIF(p.name,''), inv.product_name) LIKE ? OR COALESCE(NULLIF(p.code,''), inv.product_code) LIKE ?)"
+		baseWhere += " AND (COALESCE(NULLIF(p.name,''), inv.product_name) LIKE ? OR COALESCE(NULLIF(p.code,''), inv.product_code) LIKE ? OR p.name_pinyin LIKE ? OR p.name_initials LIKE ?)"
 		like := "%" + keyword + "%"
-		args = append(args, like, like)
+		args = append(args, like, like, like, like)
 	}
 	if warehouseIDStr != "" {
 		baseWhere += " AND inv.warehouse_id = ?"

backend/internal/handler/product.go

@@ -15,6 +15,7 @@ import (
 	"github.com/wangjia/jiu/backend/config"
 	"github.com/wangjia/jiu/backend/internal/middleware"
 	"github.com/wangjia/jiu/backend/internal/model"
+	"github.com/wangjia/jiu/backend/internal/util"
 )
 
 type ProductHandler struct {
@@ -70,6 +71,7 @@ func (h *ProductHandler) Create(c *gin.Context) {
 	}
 	product.ShopID = shopID
 	product.PublicID = uuid.New().String()
+	product.NamePinyin, product.NameInitials = util.ToPinyin(product.Name)
 
 	// Auto-generate product code if not provided (e.g. P001, P002)
 	// Retry up to 5 times on duplicate key to handle concurrent creates
@@ -122,6 +124,7 @@ func (h *ProductHandler) Update(c *gin.Context) {
 		return
 	}
 
+	namePinyin, nameInitials := util.ToPinyin(req.Name)
 	// 只更新业务字段，防止 Save() 覆盖 shop_id / created_at 等系统字段
 	if err := h.db.Model(&product).Updates(map[string]interface{}{
 		"code":           req.Code,
@@ -138,6 +141,8 @@ func (h *ProductHandler) Update(c *gin.Context) {
 		"description":    req.Description,
 		"remark":         req.Remark,
 		"custom_fields":  req.CustomFields,
+		"name_pinyin":    namePinyin,
+		"name_initials":  nameInitials,
 	}).Error; err != nil {
 		c.JSON(http.StatusInternalServerError, gin.H{"error": err.Error()})
 		return
@@ -226,13 +231,16 @@ func (h *ProductHandler) FindOrCreate(c *gin.Context) {
 
 	var count int64
 	h.db.Model(&model.Product{}).Where("shop_id = ? AND deleted_at IS NULL", shopID).Count(&count)
+	namePinyin, nameInitials := util.ToPinyin(req.Name)
 	product = model.Product{
-		TenantBase: model.TenantBase{ShopID: shopID},
-		PublicID:   uuid.New().String(),
-		Name:       req.Name,
-		Series:     req.Series,
-		Spec:       req.Spec,
-		Code:       fmt.Sprintf("P%03d", count+1),
+		TenantBase:   model.TenantBase{ShopID: shopID},
+		PublicID:     uuid.New().String(),
+		Name:         req.Name,
+		Series:       req.Series,
+		Spec:         req.Spec,
+		Code:         fmt.Sprintf("P%03d", count+1),
+		NamePinyin:   namePinyin,
+		NameInitials: nameInitials,
 	}
 	if createErr := h.db.Create(&product).Error; createErr != nil {
 		// Race condition: try to find the record created by another request