feat: new classrooms default to 'reserved' status instead of 'available'

apps/admin/src/pages/Classrooms/index.tsx

@@ -27,6 +27,7 @@ import PermissionButton from '../../components/PermissionButton';
 const statusMap: Record<string, { text: string; color: string }> = {
   available: { text: '可用', color: 'green' },
   in_use: { text: '使用中', color: 'blue' },
+  reserved: { text: '已预留', color: 'purple' },
   maintenance: { text: '维护中', color: 'orange' },
   archived: { text: '已归档', color: '#999' },
 };
@@ -223,7 +224,7 @@ const ClassroomsPage: React.FC = () => {
               if (!e.target.value) setSearchText('');
             }}
           />
-          <Select placeholder="状态" allowClear style={{ width: 110 }} value={filterStatus} onChange={setFilterStatus} options={[{value:'available',label:'可用'},{value:'in_use',label:'使用中'},{value:'maintenance',label:'维护中'}]} />
+          <Select placeholder="状态" allowClear style={{ width: 110 }} value={filterStatus} onChange={setFilterStatus} options={[{value:'available',label:'可用'},{value:'in_use',label:'使用中'},{value:'reserved',label:'已预留'},{value:'maintenance',label:'维护中'}]} />
           <Button
             type={showArchived ? 'primary' : 'default'}
             onClick={() => setShowArchived(!showArchived)}