fix: 修复打印函数缺少 try 块导致 macOS 编译失败；CI 自动安装 Git bash

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

client/lib/core/utils/print_util_stub.dart

@@ -54,6 +54,7 @@ Future<void> printProductLabelImpl({
   String shopAddress = '',
   String shopPhone = '',
 }) async {
+  try {
   final font = await _loadFont();
   final doc = pw.Document();
   final qrImage = pw.MemoryImage(qrBytes);
@@ -382,6 +383,7 @@ pw.Widget _sig(pw.Font font, pw.Font bold, String label) {
 }
 
 Future<void> printStockInOrderImpl(StockInOrder order) async {
+  try {
   final font = await _loadFont();
   final bold = await _loadBoldFont();