feat: 后台管理页全量重构 + backoffice 共享模块 + 启动脚本优化

## 后台管理页重构
- admin 端: add_doctor / doctors / home / patients 四页重构
- doctor 端: consultations / dashboard / followup_edit / followups / home / patient_detail / patients / profile / report_detail / reports / settings 十一页重构
- 新增 backoffice 共享模块: backoffice_refresh_providers + backoffice_formatters + backoffice_ui

## 后端
- AdminService 增强(分页/搜索/统计)
- doctor_endpoints 微调
- appsettings.Development 调整
- 新增 admin_service_tests

## 前端其他
- 今日健康卡片 taskRow 行高 5->7(每行 44->48px)
- 健康仪表盘配色定 #4FACFE 纯色蓝
- admin_drawer / doctor_drawer 微调
- api_client IP 适配

## 启动脚本
- start-dev.bat: 加后端就绪检测(轮询 openapi 端点, 最多等 30s)

## 清理
- 删除旧品牌图(agent_welcome_abstract / login_background_v1)
- 删除 app_status_badge 组件
- 删除旧 HANDOFF 文档, 新增 07-17 版

## 测试
- 新增 backoffice_formatters / backoffice_refresh / backoffice_ui 三个测试
- app_router_test 扩展

health_app/lib/pages/admin/admin_patients_page.dart

@@ -2,6 +2,8 @@ import 'package:flutter/material.dart';
 import 'package:flutter_riverpod/flutter_riverpod.dart';
 import '../../core/app_colors.dart';
 import '../../providers/data_providers.dart' show adminServiceProvider;
+import '../../utils/backoffice_formatters.dart';
+import '../../widgets/backoffice_ui.dart';
 
 class AdminPatientsPage extends ConsumerStatefulWidget {
   const AdminPatientsPage({super.key});
@@ -16,6 +18,7 @@ class _AdminPatientsPageState extends ConsumerState<AdminPatientsPage> {
   int _page = 1;
   bool _loading = true;
   bool _loadingMore = false;
+  String? _error;
 
   @override
   void initState() {
@@ -35,13 +38,15 @@ class _AdminPatientsPageState extends ConsumerState<AdminPatientsPage> {
       setState(() {
         _loading = true;
         _patients = [];
+        _error = null;
       });
     }
     try {
       final res = await ref
           .read(adminServiceProvider)
           .getPatients(search: _searchCtrl.text.trim(), page: _page);
-      if (res['code'] == 0 && mounted) {
+      if (!mounted) return;
+      if (res['code'] == 0) {
         final data = res['data'] as Map<String, dynamic>? ?? {};
         setState(() {
           _total = data['total'] ?? 0;
@@ -54,12 +59,19 @@ class _AdminPatientsPageState extends ConsumerState<AdminPatientsPage> {
           _loading = false;
           _loadingMore = false;
         });
+      } else {
+        setState(() {
+          _loading = false;
+          _loadingMore = false;
+          _error = res['message']?.toString() ?? '患者列表加载失败';
+        });
       }
-    } catch (_) {
+    } catch (e) {
       if (mounted) {
         setState(() {
           _loading = false;
           _loadingMore = false;
+          _error = '患者列表加载失败';
         });
       }
     }
@@ -123,13 +135,14 @@ class _AdminPatientsPageState extends ConsumerState<AdminPatientsPage> {
         // 患者列表
         Expanded(
           child: _loading
-              ? const Center(child: CircularProgressIndicator())
+              ? const BackofficeLoadingState(message: '正在加载患者')
+              : _error != null
+              ? BackofficeErrorState(message: _error!, onRetry: _load)
               : _patients.isEmpty
-              ? const Center(
-                  child: Text(
-                    '暂无患者',
-                    style: TextStyle(color: AppColors.textHint, fontSize: 16),
-                  ),
+              ? const BackofficeEmptyState(
+                  icon: Icons.people_outline,
+                  title: '暂无患者',
+                  description: '注册患者会显示在这里',
                 )
               : NotificationListener<ScrollNotification>(
                   onNotification: (n) {
@@ -152,20 +165,14 @@ class _AdminPatientsPageState extends ConsumerState<AdminPatientsPage> {
                         );
                       }
                       final p = _patients[i];
-                      return Card(
+                      return BackofficeSectionCard(
                         margin: const EdgeInsets.only(bottom: 8),
-                        elevation: 0,
-                        shape: RoundedRectangleBorder(
-                          borderRadius: BorderRadius.circular(14),
-                          side: const BorderSide(color: AppColors.border),
-                        ),
+                        padding: EdgeInsets.zero,
                         child: ListTile(
                           leading: CircleAvatar(
                             backgroundColor: AppColors.iconBg,
                             child: Text(
-                              p['name']?.toString().isNotEmpty == true
-                                  ? p['name']!.toString()[0]
-                                  : '?',
+                              backofficeInitial(p['name']),
                               style: const TextStyle(color: AppColors.primary),
                             ),
                           ),