feat(backend): 出入库编码搜索双路匹配+建单填快照；finance 趋势/日期区间；partner/product 拼音搜索

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01JJ1g8XV1YhhmHRzhwWEW7o

backend/internal/handler/stock_in_test.go

@@ -578,6 +578,45 @@ func TestStockInHandler_List_FilterByKeyword(t *testing.T) {
 	assert.Equal(t, float64(2), parseResponse(w)["total"].(float64))
 }
 
+// keyword 匹配主数据编码 p.code：明细快照编码为空时仍可按编码搜到（与出库同款双匹配）
+func TestStockInHandler_List_KeywordMatchesMasterCode(t *testing.T) {
+	db := testutil.SetupTestDB()
+	shop := testutil.CreateTestShop(db, "SI_MCODE")
+	user := testutil.CreateTestUser(db, shop.ID, "admin", "pass", "admin")
+	warehouse := testutil.CreateTestWarehouse(db, shop.ID, "Warehouse")
+	token := getAuthToken(user.ID, shop.ID, "admin")
+	r := setupProtectedRouter(db)
+
+	product := &model.Product{
+		TenantBase: model.TenantBase{ShopID: shop.ID},
+		Code:       "ZXZ030001",
+		Name:       "山崎12年",
+	}
+	require.NoError(t, db.Create(product).Error)
+
+	order := &model.StockInOrder{
+		TenantBase:  model.TenantBase{ShopID: shop.ID},
+		OrderNo:     "RK-MCODE-001",
+		WarehouseID: warehouse.ID,
+		OperatorID:  user.ID,
+		Status:      "approved",
+		OrderDate:   model.Date{Time: time.Now()},
+	}
+	require.NoError(t, db.Create(order).Error)
+	require.NoError(t, db.Create(&model.StockInItem{
+		OrderID:   order.ID,
+		ShopID:    shop.ID,
+		ProductID: product.ID,
+		Quantity:  1.0,
+	}).Error)
+
+	w := makeRequest(r, "GET", "/api/v1/stock-in/orders?keyword=ZXZ030001", token, nil)
+	assert.Equal(t, float64(1), parseResponse(w)["total"].(float64))
+
+	w = makeRequest(r, "GET", "/api/v1/stock-in/orders?keyword=ZXZ999999", token, nil)
+	assert.Equal(t, float64(0), parseResponse(w)["total"].(float64))
+}
+
 func TestStockInHandler_List_FilterByProductName(t *testing.T) {
 	db := testutil.SetupTestDB()
 	shop := testutil.CreateTestShop(db, "SI012")