fix(client): 出入库抽屉生产日期截取防空串崩溃

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

client/lib/core/utils/date_util.dart

@@ -12,6 +12,16 @@ DateTime? parseYmd(String? s) {
   return DateTime.tryParse(t);
 }
 
+/// 安全截取日期字符串前 10 位（`yyyy-MM-dd`）。
+///
+/// null 或空串一律返回 null（视为「无值」，供上层「两值皆空不渲染」的逻辑判断）；
+/// 长度不足 10 原样返回。用于兜底后端 `Date` 零值序列化为 `""`（而非 null）、
+/// 或历史导入数据缺失生产日期的场景，避免 `''.substring(0, 10)` 抛 RangeError。
+String? shortDate(String? v) {
+  if (v == null || v.isEmpty) return null;
+  return v.length >= 10 ? v.substring(0, 10) : v;
+}
+
 /// 组合年/月/日为 `yyyy-MM-dd`，自动把超出当月的「日」clamp 回当月最大值
 /// （如 2 月选 31 → 28/29）。任一为空返回 null。
 String? composeYmd(int? year, int? month, int? day) {

client/lib/screens/stock_in/stock_in_list_screen.dart

@@ -1,3 +1,4 @@
+import '../../core/utils/date_util.dart';
 import '../../core/utils/dialog_util.dart';
 import '../../core/exceptions.dart';
 import '../../core/utils/print_util.dart' show LabelData;
@@ -996,9 +997,7 @@ class _StockInListScreenState extends ConsumerState<StockInListScreen> {
                 price: it.costPrice == 0 ? '待定价' : _num.format(it.costPrice),
                 amount: it.costAmount == 0 ? '待定价' : _num.format(it.costAmount),
                 pending: it.costPrice == 0,
-                productionDate: it.productionDate != null
-                    ? it.productionDate!.substring(0, 10)
-                    : null,
+                productionDate: shortDate(it.productionDate),
                 batchNo: it.batchNo,
               ))
           .toList(),

client/lib/screens/stock_out/stock_out_list_screen.dart

@@ -5,6 +5,7 @@ import 'package:go_router/go_router.dart';
 import 'package:intl/intl.dart';
 import 'package:lucide_icons_flutter/lucide_icons.dart';
 
+import '../../core/utils/date_util.dart';
 import '../../core/utils/dialog_util.dart';
 import '../../core/exceptions.dart';
 import '../../core/responsive/responsive.dart';
@@ -1076,9 +1077,7 @@ class _StockOutListScreenState extends ConsumerState<StockOutListScreen> {
           cost: admin ? _num.format(it.costPrice) : null,
           profit: admin ? (pending ? '待定价' : _num.format(profit)) : null,
           pending: pending,
-          productionDate: it.productionDate != null
-              ? it.productionDate!.substring(0, 10)
-              : null,
+          productionDate: shortDate(it.productionDate),
           batchNo: it.batchNo,
         );
       }).toList(),