feat(client): 新增入库单/出库单打印，增强商品标签打印布局

- 商品标签改为 4×2 英寸横向，二维码右置，左侧展示系列/规格/批次/生产日期
- 新增 printStockInOrder：A4 入库单，含单号/供应商/仓库/明细表/签字栏
- 新增 printStockOutOrder：A4 出库通知单（温馨提示），含客户/明细表/签字栏
- 入库单/出库单编辑页加载完成后显示「打印」按钮

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

client/lib/screens/products/product_detail_screen.dart

@@ -533,6 +533,7 @@ class _QRCodeDialogState extends ConsumerState<_QRCodeDialog> {
         name: p.name,
         code: p.code,
         spec: p.spec,
+        series: p.series,
       );
     } catch (e) {
       if (mounted) {

client/lib/screens/stock_in/stock_in_form_screen.dart

@@ -4,6 +4,8 @@ import 'package:flutter_riverpod/flutter_riverpod.dart';
 import 'package:go_router/go_router.dart';
 import '../../core/theme/app_theme.dart';
 import '../../core/auth/auth_state.dart';
+import '../../core/utils/print_util.dart';
+import '../../models/stock_in.dart';
 import '../../providers/partner_provider.dart';
 import '../../providers/product_option_provider.dart';
 import '../../providers/product_provider.dart';
@@ -29,6 +31,7 @@ class _StockInFormScreenState extends ConsumerState<StockInFormScreen> {
   bool _submitting = false;
   bool _loadingEdit = false;
   Map<int, double> _inventoryMap = {};
+  StockInOrder? _loadedOrder;
 
   final List<_ItemRow> _items = [];
 
@@ -53,6 +56,7 @@ class _StockInFormScreenState extends ConsumerState<StockInFormScreen> {
       final specOpts = await ref.read(productSpecListProvider.future);
 
       setState(() {
+        _loadedOrder = order;
         _warehouseId = order.warehouseId;
         _partnerId = order.partnerId;
         if (order.orderDate != null) {
@@ -124,6 +128,11 @@ class _StockInFormScreenState extends ConsumerState<StockInFormScreen> {
     });
   }
 
+  Future<void> _printOrder() async {
+    if (_loadedOrder == null) return;
+    await printStockInOrder(_loadedOrder!);
+  }
+
   Future<void> _submit(bool asDraft) async {
     if (!asDraft && !_formKey.currentState!.validate()) return;
     if (_warehouseId == null) {
@@ -248,6 +257,14 @@ class _StockInFormScreenState extends ConsumerState<StockInFormScreen> {
                 Text(_isEdit ? '修改入库单' : '新建入库单',
                     style: const TextStyle(fontSize: 16, fontWeight: FontWeight.w600)),
                 const Spacer(),
+                if (_isEdit && _loadedOrder != null) ...[
+                  OutlinedButton.icon(
+                    onPressed: _printOrder,
+                    icon: const Icon(Icons.print_outlined, size: 16),
+                    label: const Text('打印'),
+                  ),
+                  const SizedBox(width: 8),
+                ],
                 OutlinedButton(
                   onPressed: _submitting ? null : () => _submit(true),
                   child: const Text('保存草稿'),

client/lib/screens/stock_out/stock_out_form_screen.dart

@@ -4,6 +4,8 @@ import 'package:flutter_riverpod/flutter_riverpod.dart';
 import 'package:go_router/go_router.dart';
 import '../../core/theme/app_theme.dart';
 import '../../core/auth/auth_state.dart';
+import '../../core/utils/print_util.dart';
+import '../../models/stock_out.dart';
 import '../../providers/inventory_provider.dart';
 import '../../providers/partner_provider.dart';
 import '../../providers/product_option_provider.dart';
@@ -29,6 +31,7 @@ class _StockOutFormScreenState extends ConsumerState<StockOutFormScreen> {
   bool _submitting = false;
   bool _loadingEdit = false;
   Map<int, double> _inventoryMap = {};
+  StockOutOrder? _loadedOrder;
 
   final List<_ItemRow> _items = [];
 
@@ -53,6 +56,7 @@ class _StockOutFormScreenState extends ConsumerState<StockOutFormScreen> {
       final specOpts = await ref.read(productSpecListProvider.future);
 
       setState(() {
+        _loadedOrder = order;
         _warehouseId = order.warehouseId;
         _partnerId = order.partnerId;
         if (order.orderDate != null) {
@@ -125,6 +129,11 @@ class _StockOutFormScreenState extends ConsumerState<StockOutFormScreen> {
     });
   }
 
+  Future<void> _printOrder() async {
+    if (_loadedOrder == null) return;
+    await printStockOutOrder(_loadedOrder!);
+  }
+
   Future<void> _submit(bool asDraft) async {
     if (!asDraft && !_formKey.currentState!.validate()) return;
     if (_warehouseId == null) {
@@ -248,6 +257,14 @@ class _StockOutFormScreenState extends ConsumerState<StockOutFormScreen> {
                 Text(_isEdit ? '修改出库单' : '新建出库单',
                     style: const TextStyle(fontSize: 16, fontWeight: FontWeight.w600)),
                 const Spacer(),
+                if (_isEdit && _loadedOrder != null) ...[
+                  OutlinedButton.icon(
+                    onPressed: _printOrder,
+                    icon: const Icon(Icons.print_outlined, size: 16),
+                    label: const Text('打印'),
+                  ),
+                  const SizedBox(width: 8),
+                ],
                 OutlinedButton(
                   onPressed: _submitting ? null : () => _submit(true),
                   child: const Text('保存草稿'),