feat(client): 登录/注册页照原型重建，ds 真相源组件族统一全部屏

- 登录/注册（login.html/register.html 1:1）：两栏卡片+品牌渐变面板+主题小衣服
  pill（onSurface 变体）+记住我（记录并预填最近账号）+原型式 toast 校验；
  登录 fidelity 1.4–2.1% 三主题全绿；注册暂不入闸（少 门店编号/兑换券 字段，
  已记 CONTRACT，screens.mjs 留存根）
- ds 原子补齐：DsToast（.toast 单例）/DsCheck（.check/.agree）/DsButton lg 档/
  DsSelect 替换全部旧 DropdownButton/DsField label 在上/DsInput 后缀与密码形态
- 全屏统一：对话框按钮全 DsButton、盒式输入主题钉死（visualDensity.standard、
  h38、InputDecorationTheme 渗漏修复）、图标全 lucide、JetBrains Mono 三端同源、
  BrandMark 真相源 logo、只读模式写操作全量守卫（WriteGuard+DsToast）
- 出入库列表：版式对齐原型（卡片对齐+搜索框居中）、KPI 近30天滚动、结清后
  失效财务应收应付表；商品编辑抽屉介绍库改搜索下拉、图片双击全屏预览
- 删除旧 UI 死代码：DataTableCard/FormDialog/PageScaffold/SearchChip/
  SelectProductDialog/tabStateProvider
- golden/fidelity：stock-in/out 补注册（9%）、login 入册（8%）、goldens 全量重打；
  修复 pubspec flutter_web_plugins 非法声明（CI pub get 阻断）

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01JJ1g8XV1YhhmHRzhwWEW7o

client/test/products_screen_test.dart

@@ -20,7 +20,8 @@ class _FakeProductNotifier extends ProductListNotifier {
   @override
   Future<PageResult<Product>> build() async {
     state = _fixed;
-    return state.value ?? const PageResult(data: [], total: 0, page: 1, pageSize: 20);
+    return state.value ??
+        const PageResult(data: [], total: 0, page: 1, pageSize: 20);
   }
 
   @override
@@ -93,7 +94,8 @@ Widget _buildLoadingApp() {
 // ---------------------------------------------------------------------------
 // TODO: ProductsScreen 已重构为 options tab 页，productListProvider 已不挂载，测试待重写
 void main() {
-  testWidgets('shows CircularProgressIndicator while loading', skip: true, (tester) async {
+  testWidgets('shows CircularProgressIndicator while loading', skip: true,
+      (tester) async {
     tester.view.physicalSize = const Size(1280, 800);
     tester.view.devicePixelRatio = 1.0;
     addTearDown(tester.view.resetPhysicalSize);
@@ -104,7 +106,8 @@ void main() {
     expect(find.byType(CircularProgressIndicator), findsOneWidget);
   });
 
-  testWidgets('shows error message on load failure', skip: true, (tester) async {
+  testWidgets('shows error message on load failure', skip: true,
+      (tester) async {
     tester.view.physicalSize = const Size(1280, 800);
     tester.view.devicePixelRatio = 1.0;
     addTearDown(tester.view.resetPhysicalSize);
@@ -136,7 +139,8 @@ void main() {
     expect(find.text('暂无商品'), findsOneWidget);
   });
 
-  testWidgets('shows product list with name code and unit', skip: true, (tester) async {
+  testWidgets('shows product list with name code and unit', skip: true,
+      (tester) async {
     tester.view.physicalSize = const Size(1280, 800);
     tester.view.devicePixelRatio = 1.0;
     addTearDown(tester.view.resetPhysicalSize);
@@ -180,7 +184,8 @@ void main() {
     expect(find.text('新建'), findsOneWidget);
   });
 
-  testWidgets('tapping 新建 opens product form dialog', skip: true, (tester) async {
+  testWidgets('tapping 新建 opens product form dialog', skip: true,
+      (tester) async {
     tester.view.physicalSize = const Size(1280, 800);
     tester.view.devicePixelRatio = 1.0;
     addTearDown(tester.view.resetPhysicalSize);
@@ -260,7 +265,8 @@ void main() {
     expect(find.text('删除'), findsAtLeastNWidgets(1));
   });
 
-  testWidgets('tapping edit opens edit dialog with prefilled values', skip: true, (tester) async {
+  testWidgets('tapping edit opens edit dialog with prefilled values',
+      skip: true, (tester) async {
     tester.view.physicalSize = const Size(1280, 800);
     tester.view.devicePixelRatio = 1.0;
     addTearDown(tester.view.resetPhysicalSize);
@@ -289,7 +295,8 @@ void main() {
     expect(find.widgetWithText(TextFormField, 'P001'), findsOneWidget);
   });
 
-  testWidgets('shows total count in pagination bar', skip: true, (tester) async {
+  testWidgets('shows total count in pagination bar', skip: true,
+      (tester) async {
     tester.view.physicalSize = const Size(1280, 800);
     tester.view.devicePixelRatio = 1.0;
     addTearDown(tester.view.resetPhysicalSize);