feat(client): 入库/出库录单表单（旗舰屏）斑马行 token 化 + 整屏 golden

录单明细网格斑马行 Colors.white/FFFAFAFA → surface/bg（修暗色破绽，两表单
现 0 硬编码色残留）；入库+出库录单表单整屏 golden ×三主题（桌面+移动）入回归闸，
锁住 单据信息卡 + 可编辑明细网格 + 底栏。

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01TSKEiHsvauyxYUW2itzUXX

client/lib/screens/stock_in/stock_in_form_screen.dart

@@ -1024,7 +1024,7 @@ class _StockInFormScreenState extends ConsumerState<StockInFormScreen> {
       children: [
         IntrinsicHeight(
           child: Container(
-            color: index.isEven ? Colors.white : const Color(0xFFFAFAFA),
+            color: index.isEven ? context.tokens.surface : context.tokens.bg,
             child:
                 Row(crossAxisAlignment: CrossAxisAlignment.center, children: [
               SizedBox(

client/lib/screens/stock_out/stock_out_form_screen.dart

@@ -757,7 +757,7 @@ class _StockOutFormScreenState extends ConsumerState<StockOutFormScreen> {
 
     return TableRow(
       decoration: BoxDecoration(
-        color: index.isEven ? Colors.white : const Color(0xFFFAFAFA),
+        color: index.isEven ? context.tokens.surface : context.tokens.bg,
       ),
       children: [
         // 序号