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/lib/widgets/ds/ds_kpi.dart

@@ -2,6 +2,7 @@
 import 'package:flutter/material.dart';
 import '../../core/theme/context_tokens.dart';
 import '../../core/theme/app_dims.g.dart';
+import '../../core/theme/app_fonts.dart';
 
 /// 图标块 .ic 变体（软底 + 前景色）。
 enum DsKpiTone { info, ok, blue, alert }
@@ -14,7 +15,8 @@ enum DsKpiDelta { up, down, neutral }
 class DsKpi extends StatelessWidget {
   final String title;
   final String value;
-  final IconData icon;
+  // 原型 users.html 的 KPI 无右上图标块 → icon 可空时不渲染 .ic
+  final IconData? icon;
   final DsKpiTone tone;
   final String? delta;
   final DsKpiDelta deltaTone;
@@ -24,7 +26,7 @@ class DsKpi extends StatelessWidget {
     super.key,
     required this.title,
     required this.value,
-    required this.icon,
+    this.icon,
     this.tone = DsKpiTone.info,
     this.delta,
     this.deltaTone = DsKpiDelta.neutral,
@@ -63,19 +65,19 @@ class DsKpi extends StatelessWidget {
                 child: Padding(
                   padding: const EdgeInsets.only(top: 2),
                   child: Text(title,
-                      style: TextStyle(
-                          fontSize: AppDims.fsSm, color: t.muted)),
+                      style: TextStyle(fontSize: AppDims.fsSm, color: t.muted)),
                 ),
               ),
-              Container(
-                width: 30,
-                height: 30,
-                decoration: BoxDecoration(
-                    color: icBg,
-                    borderRadius: BorderRadius.circular(AppDims.rMd)),
-                alignment: Alignment.center,
-                child: Icon(icon, size: 17, color: icFg),
-              ),
+              if (icon != null)
+                Container(
+                  width: 30,
+                  height: 30,
+                  decoration: BoxDecoration(
+                      color: icBg,
+                      borderRadius: BorderRadius.circular(AppDims.rMd)),
+                  alignment: Alignment.center,
+                  child: Icon(icon, size: 17, color: icFg),
+                ),
             ],
           ),
           const SizedBox(height: 7),
@@ -84,23 +86,19 @@ class DsKpi extends StatelessWidget {
                   fontSize: 24,
                   fontWeight: FontWeight.w700,
                   letterSpacing: 0.3,
-                  fontFamily: 'monospace',
+                  fontFamily: AppFonts.mono,
+                  fontFamilyFallback: AppFonts.monoFallback,
                   color: tone == DsKpiTone.alert ? t.accent : t.heading)),
           if (delta != null) ...[
             const SizedBox(height: 5),
-            Row(
-              mainAxisSize: MainAxisSize.min,
-              children: [
-                if (deltaTone != DsKpiDelta.neutral)
-                  Icon(
-                      deltaTone == DsKpiDelta.up
-                          ? Icons.arrow_drop_up
-                          : Icons.arrow_drop_down,
-                      size: 14,
-                      color: deltaColor),
-                Text(delta!,
-                    style: TextStyle(fontSize: AppDims.fsXs, color: deltaColor)),
-              ],
+            // 原型 .d 的箭头是文本字符 ▲/▼（非图标），gap4。
+            Text(
+              switch (deltaTone) {
+                DsKpiDelta.up => '▲ ${delta!}',
+                DsKpiDelta.down => '▼ ${delta!}',
+                DsKpiDelta.neutral => delta!,
+              },
+              style: TextStyle(fontSize: AppDims.fsXs, color: deltaColor),
             ),
           ],
         ],