feat(grid): add export selected rows and batch restore

## 背景说明
恢复导出选中行的功能，并新增批量恢复行功能。用户现在可以在多行选中时，
通过右键菜单或工具栏导出选中的行，同时支持批量恢复已删除的行。

## 修改内容
- exportCsv/exportJson/exportMarkdown/exportXlsx 支持可选 rowIds 参数
- 新增 rowsToExport 辅助函数，根据 rowIds 筛选要导出的行
- 右键菜单和工具栏新增"导出选中行"选项（CSV/XLSX/JSON/Markdown）
- 新增 restoreRows 函数支持批量恢复已删除行
- 更新上下文菜单中恢复行的文案，支持单数/复数切换
- 补充 en/es/zh-CN 三语言国际化文案

## 测试
- 建议补充：导出函数传入特定 rowIds 的筛选逻辑测试
- 建议补充：批量恢复已删除行的单元测试
- 建议补充：多选时状态栏显示边界测试

src/components/grid/DataGrid.vue

@@ -927,6 +927,7 @@ const {
   requestDeleteRow,
   confirmDeleteRow,
   restoreRow,
+  restoreRows,
   pendingDeleteRowIds,
   requestDeleteRows,
   cloneRows,
@@ -1111,6 +1112,22 @@ function affectedRowIds(): number[] {
   return [];
 }
 
+function exportSelectedRowsCsv() {
+  return exportCsv(affectedRowIds());
+}
+
+function exportSelectedRowsXlsx() {
+  return exportXlsx(affectedRowIds());
+}
+
+function exportSelectedRowsJson() {
+  return exportJson(affectedRowIds());
+}
+
+function exportSelectedRowsMarkdown() {
+  return exportMarkdown(affectedRowIds());
+}
+
 function isRowActive(index: number): boolean {
   const item = displayItems.value[index];
   if (item && isRowSelected(item.id)) return true;
@@ -2620,8 +2637,12 @@ defineExpose({
             <CopyPlus class="w-3.5 h-3.5 mr-2" />
             {{ isMultiRow ? t("grid.cloneRows", { count: multiRowCount }) : t("grid.cloneRow") }}
           </ContextMenuItem>
-          <ContextMenuItem v-if="contextRowItem.isDeleted" @click="restoreRow(contextRowItem.id)">
-            <Undo2 class="w-3.5 h-3.5 mr-2" /> {{ t("grid.restoreRow") }}
+          <ContextMenuItem
+            v-if="contextRowItem.isDeleted"
+            @click="isMultiRow ? restoreRows(affectedRowIds()) : restoreRow(contextRowItem.id)"
+          >
+            <Undo2 class="w-3.5 h-3.5 mr-2" />
+            {{ isMultiRow ? t("grid.restoreRows", { count: multiRowCount }) : t("grid.restoreRow") }}
           </ContextMenuItem>
           <ContextMenuItem
             v-else
@@ -2640,6 +2661,15 @@ defineExpose({
             <ContextMenuItem @click="exportXlsx">{{ t("grid.exportXlsx") }}</ContextMenuItem>
             <ContextMenuItem @click="exportJson">{{ t("grid.exportJson") }}</ContextMenuItem>
             <ContextMenuItem @click="exportMarkdown">{{ t("grid.exportMarkdown") }}</ContextMenuItem>
+            <template v-if="isMultiRow">
+              <ContextMenuSeparator />
+              <ContextMenuItem @click="exportSelectedRowsCsv">{{ t("grid.exportSelectedRowsCsv") }}</ContextMenuItem>
+              <ContextMenuItem @click="exportSelectedRowsXlsx">{{ t("grid.exportSelectedRowsXlsx") }}</ContextMenuItem>
+              <ContextMenuItem @click="exportSelectedRowsJson">{{ t("grid.exportSelectedRowsJson") }}</ContextMenuItem>
+              <ContextMenuItem @click="exportSelectedRowsMarkdown">{{
+                t("grid.exportSelectedRowsMarkdown")
+              }}</ContextMenuItem>
+            </template>
           </ContextMenuSubContent>
         </ContextMenuSub>
       </ContextMenuContent>
@@ -2664,7 +2694,7 @@ defineExpose({
       <span v-if="result.truncated" class="text-amber-500 text-xs ml-1">(truncated)</span>
       <span v-if="!hasData">{{ t("grid.rowsAffected", { count: result.affected_rows }) }}</span>
       <span>{{ result.execution_time_ms }}ms</span>
-      <span v-if="hasCellSelection" class="text-foreground">{{ selectionSummary }}</span>
+      <span v-if="selectedRowCount > 0 || hasCellSelection" class="text-foreground">{{ selectionSummary }}</span>
 
       <template v-if="editable && (tableMeta || customSave) && !useTransaction">
         <span v-if="hasPendingChanges" class="ml-2 text-foreground">
@@ -2718,6 +2748,15 @@ defineExpose({
           <DropdownMenuItem @click="exportXlsx">{{ t("grid.exportXlsx") }}</DropdownMenuItem>
           <DropdownMenuItem @click="exportJson">{{ t("grid.exportJson") }}</DropdownMenuItem>
           <DropdownMenuItem @click="exportMarkdown">{{ t("grid.exportMarkdown") }}</DropdownMenuItem>
+          <template v-if="isMultiRow">
+            <ContextMenuSeparator />
+            <DropdownMenuItem @click="exportSelectedRowsCsv">{{ t("grid.exportSelectedRowsCsv") }}</DropdownMenuItem>
+            <DropdownMenuItem @click="exportSelectedRowsXlsx">{{ t("grid.exportSelectedRowsXlsx") }}</DropdownMenuItem>
+            <DropdownMenuItem @click="exportSelectedRowsJson">{{ t("grid.exportSelectedRowsJson") }}</DropdownMenuItem>
+            <DropdownMenuItem @click="exportSelectedRowsMarkdown">{{
+              t("grid.exportSelectedRowsMarkdown")
+            }}</DropdownMenuItem>
+          </template>
         </DropdownMenuContent>
       </DropdownMenu>