fix(client): rebase 到 main 后适配打印线与 token 体系

main 的打印代码引用了分支已删除的 AppTheme（app_theme.dart）。按「冲突以 main 逻辑为准」
保留 main 的打印预览流程，把三处 AppTheme.* 颜色迁移到分支 token 体系：
- stock_in/out_list 单据详情顶栏：brand50/border/primaryDark → context.tokens.*
- order_print_preview_dialog：import 换 context_tokens，primary/textSecondary → tokens.primary/muted
form 屏改用 main 的 showStock{In,Out}OrderPrint 打印预览入口，随之刷新 12 张 form golden 基线。

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

client/lib/screens/stock_in/stock_in_list_screen.dart

@@ -1072,26 +1072,29 @@ class _StockInDetailDialogState extends ConsumerState<_StockInDetailDialog> {
           children: [
             Container(
               padding: const EdgeInsets.symmetric(horizontal: 8, vertical: 8),
-              decoration: const BoxDecoration(
-                color: AppTheme.brand50,
-                border: Border(bottom: BorderSide(color: AppTheme.border)),
+              decoration: BoxDecoration(
+                color: context.tokens.brand50,
+                border: Border(
+                    bottom: BorderSide(color: context.tokens.border)),
               ),
               child: Row(
                 children: [
                   IconButton(
-                    icon: const Icon(Icons.arrow_back, color: AppTheme.primaryDark),
+                    icon: Icon(Icons.arrow_back,
+                        color: context.tokens.primaryDark),
                     tooltip: '返回',
                     onPressed: () => Navigator.of(context).pop(),
                   ),
-                  const Text('入库单详情',
+                  Text('入库单详情',
                       style: TextStyle(
                           fontSize: 16,
                           fontWeight: FontWeight.w600,
-                          color: AppTheme.primaryDark)),
+                          color: context.tokens.primaryDark)),
                   const Spacer(),
                   if (_loadedOrder != null)
                     IconButton(
-                      icon: const Icon(Icons.print_outlined, color: AppTheme.primaryDark),
+                      icon: Icon(Icons.print_outlined,
+                          color: context.tokens.primaryDark),
                       tooltip: '打印',
                       onPressed: () => showStockInOrderPrint(context, ref, _loadedOrder!),
                     ),

client/lib/screens/stock_out/stock_out_list_screen.dart

@@ -983,26 +983,29 @@ class _StockOutDetailDialogState extends ConsumerState<_StockOutDetailDialog> {
           children: [
             Container(
               padding: const EdgeInsets.symmetric(horizontal: 8, vertical: 8),
-              decoration: const BoxDecoration(
-                color: AppTheme.brand50,
-                border: Border(bottom: BorderSide(color: AppTheme.border)),
+              decoration: BoxDecoration(
+                color: context.tokens.brand50,
+                border: Border(
+                    bottom: BorderSide(color: context.tokens.border)),
               ),
               child: Row(
                 children: [
                   IconButton(
-                    icon: const Icon(Icons.arrow_back, color: AppTheme.primaryDark),
+                    icon: Icon(Icons.arrow_back,
+                        color: context.tokens.primaryDark),
                     tooltip: '返回',
                     onPressed: () => Navigator.of(context).pop(),
                   ),
-                  const Text('出库单详情',
+                  Text('出库单详情',
                       style: TextStyle(
                           fontSize: 16,
                           fontWeight: FontWeight.w600,
-                          color: AppTheme.primaryDark)),
+                          color: context.tokens.primaryDark)),
                   const Spacer(),
                   if (_loadedOrder != null)
                     IconButton(
-                      icon: const Icon(Icons.print_outlined, color: AppTheme.primaryDark),
+                      icon: Icon(Icons.print_outlined,
+                          color: context.tokens.primaryDark),
                       tooltip: '打印',
                       onPressed: () => showStockOutOrderPrint(context, ref, _loadedOrder!),
                     ),

client/lib/widgets/order_print_preview_dialog.dart

@@ -5,7 +5,7 @@ import 'package:flutter_riverpod/flutter_riverpod.dart';
 import 'package:printing/printing.dart';
 import '../core/auth/auth_state.dart';
 import '../core/errors/error_reporter.dart';
-import '../core/theme/app_theme.dart';
+import '../core/theme/context_tokens.dart';
 import '../core/responsive/responsive.dart';
 import '../core/utils/print_util.dart';
 import '../models/shop.dart';
@@ -112,9 +112,9 @@ class _OrderPrintPreviewDialogState extends State<OrderPrintPreviewDialog> {
             Container(
               padding:
                   const EdgeInsets.symmetric(horizontal: 20, vertical: 14),
-              decoration: const BoxDecoration(
-                color: AppTheme.primary,
-                borderRadius: BorderRadius.only(
+              decoration: BoxDecoration(
+                color: context.tokens.primary,
+                borderRadius: const BorderRadius.only(
                   topLeft: Radius.circular(12),
                   topRight: Radius.circular(12),
                 ),
@@ -163,7 +163,7 @@ class _OrderPrintPreviewDialogState extends State<OrderPrintPreviewDialog> {
                           fontSize: 12,
                           color: _error.isNotEmpty
                               ? Colors.red
-                              : AppTheme.textSecondary),
+                              : context.tokens.muted),
                     ),
                   ),
                   TextButton(