feat(client): 库存查询新增规格/系列/入库时间；筛选组件支持搜索+滚动+标签

- 库存查询加规格、系列服务端筛选（后端 IN 条件，前端从 product-options API 加载全量选项）
- 库存查询新增「入库时间」列，导出 Excel 同步带上
- 入库单商品明细：隐藏商品编码列，生产日期从选填折叠区移至主行常显
- 筛选弹窗重构：顶部搜索框实时过滤 + 滚动列表（ConstrainedBox maxHeight）根治溢出
- 已选项以 Chip 标签置顶展示，每个标签带 × 可单独取消
- FilterableColumnHeader 筛选图标改为常驻，不再需要 hover 才显示

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

client/lib/screens/stock_in/stock_in_form_screen.dart

@@ -842,10 +842,10 @@ class _StockInFormScreenState extends ConsumerState<StockInFormScreen> {
       color: const Color(0xFFF0F4FF),
       child: Row(children: [
         SizedBox(width: 36, child: th('序号')),
-        Expanded(flex: 12, child: th('商品编码')),
         Expanded(flex: 20, child: th('名称')),
         Expanded(flex: 13, child: th('系列')),
         Expanded(flex: 13, child: th('规格')),
+        Expanded(flex: 12, child: th('生产日期')),
         Expanded(flex: 9, child: th('单品数量')),
         Expanded(flex: 10, child: th('数量')),
         Expanded(flex: 10, child: th('单价')),
@@ -875,7 +875,6 @@ class _StockInFormScreenState extends ConsumerState<StockInFormScreen> {
         );
 
     final hasOptional = item.batchNoCtrl.text.isNotEmpty ||
-        item.productionDate != null ||
         item.selectedOriginId != null ||
         item.selectedShelfLifeId != null ||
         item.selectedStorageId != null ||
@@ -891,9 +890,6 @@ class _StockInFormScreenState extends ConsumerState<StockInFormScreen> {
               SizedBox(
                   width: 36,
                   child: tc('${index + 1}', color: AppTheme.textSecondary)),
-              Expanded(
-                  flex: 12,
-                  child: tc(productCode, color: AppTheme.textSecondary)),
               Expanded(
                   flex: 20,
                   child: Padding(
@@ -909,6 +905,11 @@ class _StockInFormScreenState extends ConsumerState<StockInFormScreen> {
                   child: Padding(
                       padding: const EdgeInsets.all(4),
                       child: _specField(item))),
+              Expanded(
+                  flex: 12,
+                  child: Padding(
+                      padding: const EdgeInsets.all(4),
+                      child: _dateField(item))),
               Expanded(
                   flex: 9,
                   child: tc(specQty > 0 ? '$specQty' : '-',
@@ -994,8 +995,6 @@ class _StockInFormScreenState extends ConsumerState<StockInFormScreen> {
             children: [
               _OptionalField(
                   label: '批次号', width: 180, child: _batchField(item)),
-              _OptionalField(
-                  label: '生产日期', width: 160, child: _dateField(item)),
               _OptionalField(
                   label: '产地', width: 180, child: _originField(item)),
               _OptionalField(
@@ -1022,7 +1021,6 @@ class _StockInFormScreenState extends ConsumerState<StockInFormScreen> {
 
     return MobileListCard(
       title: Text('商品 ${index + 1}'),
-      subtitle: productCode.isNotEmpty ? Text('编码 $productCode') : null,
       trailing: IconButton(
         icon: const Icon(Icons.delete_outline, size: 20, color: AppTheme.danger),
         onPressed: _items.length > 1 ? () => _removeItem(index) : null,
@@ -1033,6 +1031,7 @@ class _StockInFormScreenState extends ConsumerState<StockInFormScreen> {
         MobileCardField('名称', null, valueWidget: _nameField(item)),
         MobileCardField('系列', null, valueWidget: _seriesField(item)),
         MobileCardField('规格', null, valueWidget: _specField(item)),
+        MobileCardField('生产日期', null, valueWidget: _dateField(item)),
         MobileCardField('单品数量', specQty > 0 ? '$specQty' : '-'),
         MobileCardField('数量', null, valueWidget: _qtyField(item)),
         MobileCardField('单价', null, valueWidget: _priceField(item)),
@@ -1051,8 +1050,6 @@ class _StockInFormScreenState extends ConsumerState<StockInFormScreen> {
             )),
         if (item.expanded)
           MobileCardField('批次号', null, valueWidget: _batchField(item)),
-        if (item.expanded)
-          MobileCardField('生产日期', null, valueWidget: _dateField(item)),
         if (item.expanded)
           MobileCardField('产地', null, valueWidget: _originField(item)),
         if (item.expanded)