fix: 管理员系统 + 注册流程重构 + UI改版 + 全链路修复

- 新增管理员角色(手机号12345678910)，管理员可增删医生、查看患者
- 注册页重构：去掉角色选择+审核码，改为选医生+填姓名
- 医生端点按DoctorId过滤患者，Patient↔Doctor关系建立
- Doctor/DoctorProfile/User实体新增关联字段
- JSON循环引用修复(IgnoreCycles)
- /api/doctors改为公开接口
- 登录闪屏修复+原生Android启动页
- 输入框全局白底+灰框
- 蓝牙重连同步修复
- Web端(doctor_web+health_app/web)全部删除
- 全局UI改版：白底企业风，新配色和组件系统
- 新品牌图标和启动图

health_app/lib/widgets/app_empty_state.dart

@@ -1,7 +1,6 @@
 import 'package:flutter/material.dart';
-import 'package:shadcn_ui/shadcn_ui.dart';
+import '../core/app_colors.dart';
 
-/// 统一空状态占位组件
 class AppEmptyState extends StatelessWidget {
   final IconData icon;
   final String title;
@@ -18,7 +17,6 @@ class AppEmptyState extends StatelessWidget {
 
   @override
   Widget build(BuildContext context) {
-    final theme = ShadTheme.of(context);
     return Center(
       child: Padding(
         padding: const EdgeInsets.all(48),
@@ -29,21 +27,34 @@ class AppEmptyState extends StatelessWidget {
               width: 80,
               height: 80,
               decoration: BoxDecoration(
-                color: theme.colorScheme.muted,
+                color: AppColors.iconBg,
                 borderRadius: BorderRadius.circular(40),
+                border: Border.all(color: AppColors.border),
               ),
-              child: Icon(icon, size: 36, color: theme.colorScheme.mutedForeground),
+              child: Icon(icon, size: 34, color: AppColors.primary),
+            ),
+            const SizedBox(height: 18),
+            Text(
+              title,
+              style: const TextStyle(
+                fontSize: 18,
+                fontWeight: FontWeight.w700,
+                color: AppColors.textPrimary,
+              ),
+              textAlign: TextAlign.center,
             ),
-            const SizedBox(height: 20),
-            Text(title, style: TextStyle(fontSize: 20, fontWeight: FontWeight.w600, color: theme.colorScheme.foreground)),
             if (subtitle != null) ...[
               const SizedBox(height: 6),
-              Text(subtitle!, style: TextStyle(fontSize: 17, color: theme.colorScheme.mutedForeground), textAlign: TextAlign.center),
-            ],
-            if (action != null) ...[
-              const SizedBox(height: 20),
-              action!,
+              Text(
+                subtitle!,
+                style: const TextStyle(
+                  fontSize: 14,
+                  color: AppColors.textSecondary,
+                ),
+                textAlign: TextAlign.center,
+              ),
             ],
+            if (action != null) ...[const SizedBox(height: 20), action!],
           ],
         ),
       ),