chore: 干净 ERP 基座 — 删除 health/ai/wechat 业务代码

删除内容:
- 前端: health/(67文件), ai/(2文件), Copilot, MediaPicker, 相关API/Store/Hook
- 后端: wechat_handler, wechat_service, wechat_user entity, analytics handler, ai_workflow_seed
- 配置: WechatConfig, AppConfig.wechat, AuthState wechat 字段
- 启动: 微信凭据检查块, ensure_ai_workflows() 调用
- 迁移: 新增 m20260613_000170_drop_wechat_users.rs
- 脚本: api_test_health_alert.py, api_test_mp.py, mpsync.sh/ps1
- E2E: health-data page, flows/ 目录

保留: erp-core/auth/workflow/message/config/plugin + 基座前端 + 通用组件

apps/web/src/pages/Messages.tsx

@@ -0,0 +1,72 @@
+import { useState } from 'react';
+import { Tabs } from 'antd';
+import { BellOutlined, MailOutlined, FileTextOutlined, SettingOutlined } from '@ant-design/icons';
+import NotificationList from './messages/NotificationList';
+import MessageTemplates from './messages/MessageTemplates';
+import NotificationPreferences from './messages/NotificationPreferences';
+import type { MessageQuery } from '../api/messages';
+
+const UNREAD_FILTER: MessageQuery = { is_read: false };
+
+export default function Messages() {
+  const [activeKey, setActiveKey] = useState('all');
+
+  return (
+    <div>
+      <div className="erp-page-header" style={{ borderBottom: 'none', marginBottom: 0, paddingBottom: 8 }}>
+        <div>
+          <h4>消息中心</h4>
+          <div className="erp-page-subtitle">管理站内消息、模板和通知偏好</div>
+        </div>
+      </div>
+
+      <Tabs
+        activeKey={activeKey}
+        onChange={setActiveKey}
+        style={{ marginTop: 8 }}
+        items={[
+          {
+            key: 'all',
+            label: (
+              <span style={{ display: 'flex', alignItems: 'center', gap: 6 }}>
+                <MailOutlined style={{ fontSize: 14 }} />
+                全部消息
+              </span>
+            ),
+            children: <NotificationList />,
+          },
+          {
+            key: 'unread',
+            label: (
+              <span style={{ display: 'flex', alignItems: 'center', gap: 6 }}>
+                <BellOutlined style={{ fontSize: 14 }} />
+                未读消息
+              </span>
+            ),
+            children: <NotificationList queryFilter={UNREAD_FILTER} />,
+          },
+          {
+            key: 'templates',
+            label: (
+              <span style={{ display: 'flex', alignItems: 'center', gap: 6 }}>
+                <FileTextOutlined style={{ fontSize: 14 }} />
+                消息模板
+              </span>
+            ),
+            children: <MessageTemplates />,
+          },
+          {
+            key: 'preferences',
+            label: (
+              <span style={{ display: 'flex', alignItems: 'center', gap: 6 }}>
+                <SettingOutlined style={{ fontSize: 14 }} />
+                通知设置
+              </span>
+            ),
+            children: <NotificationPreferences />,
+          },
+        ]}
+      />
+    </div>
+  );
+}