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/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(