fix(backend): 入库审核库存沿用明细真实快照名 + 库存列表过滤软删商品，修复历史导入占位顶替；入库/出库列表支持 keyword 搜索

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01YZ4DskSRKsSiheQonFtQvx

backend/internal/handler/inventory_test.go

@@ -219,6 +219,52 @@ func TestInventoryHandler_List_HotelIsolation(t *testing.T) {
 	assert.Equal(t, float64(0), respB["total"].(float64))
 }
 
+// 库存指向已软删的占位商品时，列表应回退到明细/库存快照真名，
+// 而非占位商品名「历史导入占位」，且能按真名搜索到。
+func TestInventoryHandler_List_DeletedProductFallsBackToSnapshot(t *testing.T) {
+	db := testutil.SetupTestDB()
+	shop := testutil.CreateTestShop(db, "INV009")
+	user := testutil.CreateTestUser(db, shop.ID, "admin", "pass", "admin")
+	warehouse := testutil.CreateTestWarehouse(db, shop.ID, "Warehouse")
+	placeholder := testutil.CreateTestProduct(db, shop.ID, "历史导入占位")
+	token := getAuthToken(user.ID, shop.ID, "admin")
+	r := setupProtectedRouter(db)
+
+	// 明细携带真实快照名
+	item := model.StockInItem{
+		ShopID:      shop.ID,
+		ProductID:   placeholder.ID,
+		ProductCode: "ZXZ029751",
+		ProductName: "贵州茅台酒2006",
+		Quantity:    10,
+	}
+	require.NoError(t, db.Create(&item).Error)
+
+	// 库存：product_id 指向占位商品，且 product_name 也是占位名（模拟旧脏数据）
+	require.NoError(t, db.Create(&model.Inventory{
+		ShopID:        shop.ID,
+		WarehouseID:   &warehouse.ID,
+		ProductID:     &placeholder.ID,
+		StockInItemID: &item.ID,
+		ProductName:   "历史导入占位",
+		Quantity:      10,
+	}).Error)
+
+	// 软删占位商品
+	require.NoError(t, db.Delete(&placeholder).Error)
+
+	// 列表：名称应回退到明细快照真名
+	w := makeRequest(r, "GET", "/api/v1/inventory", token, nil)
+	resp := parseResponse(w)
+	require.Equal(t, float64(1), resp["total"].(float64))
+	invItem := resp["data"].([]interface{})[0].(map[string]interface{})
+	assert.Equal(t, "贵州茅台酒2006", invItem["product_name"])
+
+	// 按真名可搜到
+	w = makeRequest(r, "GET", "/api/v1/inventory?keyword=茅台", token, nil)
+	assert.Equal(t, float64(1), parseResponse(w)["total"].(float64))
+}
+
 func TestInventoryHandler_AfterStockInApprove(t *testing.T) {
 	db := testutil.SetupTestDB()
 	shop := testutil.CreateTestShop(db, "INV008")