fix(mp): 医生端添加底部导航栏解决无法退出登录问题

医生端工作台是分包页面，不在 TabBar 配置中，redirectTo 后底部
导航消失导致无法到达"我的"页面退出登录。新增 DoctorTabBar 组件
模拟底部导航，包含工作台/患者/咨询/我的四个入口，使用 reLaunch
切换避免页栈溢出。

apps/miniprogram/src/components/ui/DoctorTabBar/index.tsx

@@ -0,0 +1,47 @@
+import { View, Text } from '@tarojs/components';
+import Taro from '@tarojs/taro';
+import './index.scss';
+
+interface TabItem {
+  key: string;
+  icon: string;
+  activeIcon: string;
+  label: string;
+  url: string;
+}
+
+const DOCTOR_TABS: TabItem[] = [
+  { key: 'workbench', icon: '🏠', activeIcon: '🏠', label: '工作台', url: '/pages/pkg-doctor-core/index' },
+  { key: 'patients', icon: '👤', activeIcon: '👤', label: '患者', url: '/pages/pkg-doctor-core/patients/index' },
+  { key: 'consultation', icon: '💬', activeIcon: '💬', label: '咨询', url: '/pages/pkg-doctor-core/consultation/index' },
+  { key: 'settings', icon: '⚙️', activeIcon: '⚙️', label: '我的', url: '/pages/pkg-profile/settings/index' },
+];
+
+interface DoctorTabBarProps {
+  active?: string;
+}
+
+export default function DoctorTabBar({ active }: DoctorTabBarProps) {
+  const currentPath = `/${Taro.getCurrentPages().pop()?.path ?? ''}`;
+  const activeKey = active ?? DOCTOR_TABS.find((t) => currentPath.startsWith(t.url.replace('/index', '')))?.key ?? 'workbench';
+
+  const handleTab = (tab: TabItem) => {
+    if (tab.key === activeKey) return;
+    Taro.reLaunch({ url: tab.url });
+  };
+
+  return (
+    <View className="doctor-tabbar">
+      {DOCTOR_TABS.map((tab) => (
+        <View
+          key={tab.key}
+          className={`doctor-tabbar__item ${tab.key === activeKey ? 'doctor-tabbar__item--active' : ''}`}
+          onClick={() => handleTab(tab)}
+        >
+          <Text className="doctor-tabbar__icon">{tab.key === activeKey ? tab.activeIcon : tab.icon}</Text>
+          <Text className="doctor-tabbar__label">{tab.label}</Text>
+        </View>
+      ))}
+    </View>
+  );
+}