fix(desktop): session persistence — refresh/login/context/empty-content 4-bug fix

1. App.tsx: add restoreSession() call on startup to prevent redirect
   to login page after refresh (isRestoring guard + BootstrapScreen)
2. CloneManager: call syncAgents() after loadClones() to restore
   currentAgent and conversation history on app load
3. zclaw-memory: add get_or_create_session() so frontend session UUID
   is persisted directly — kernel no longer creates mismatched IDs
4. openai.rs: assistant message content must be non-empty for
   Kimi/Qwen APIs — replace empty content with meaningful placeholders

Also includes admin-v2 ModelServices unified page (merge providers +
models + API keys into expandable row layout)

admin-v2/src/pages/Accounts.tsx

@@ -5,10 +5,10 @@
 import { useState } from 'react'
 import { useQuery, useMutation, useQueryClient } from '@tanstack/react-query'
 import { Button, message, Tag, Modal, Form, Input, Select, Popconfirm, Space } from 'antd'
-import { PlusOutlined } from '@ant-design/icons'
 import type { ProColumns } from '@ant-design/pro-components'
 import { ProTable } from '@ant-design/pro-components'
 import { accountService } from '@/services/accounts'
+import { PageHeader } from '@/components/PageHeader'
 import type { AccountPublic } from '@/types'
 
 const roleLabels: Record<string, string> = {
@@ -116,7 +116,10 @@ export default function Accounts() {
       hideInSearch: true,
       render: (_, record) => (
         <Space>
-          <Button size="small" onClick={() => { setEditingId(record.id); form.setFieldsValue(record); setModalOpen(true) }}>
+          <Button
+            size="small"
+            onClick={() => { setEditingId(record.id); form.setFieldsValue(record); setModalOpen(true) }}
+          >
             编辑
           </Button>
           {record.status === 'active' ? (
@@ -142,6 +145,8 @@ export default function Accounts() {
 
   return (
     <div>
+      <PageHeader title="账号管理" description="管理系统用户账号、角色与权限" />
+
       <ProTable<AccountPublic>
         columns={columns}
         dataSource={data?.items ?? []}
@@ -158,13 +163,13 @@ export default function Accounts() {
       />
 
       <Modal
-        title="编辑账号"
+        title={<span className="text-base font-semibold">编辑账号</span>}
         open={modalOpen}
         onOk={handleSave}
         onCancel={() => { setModalOpen(false); setEditingId(null); form.resetFields() }}
         confirmLoading={updateMutation.isPending}
       >
-        <Form form={form} layout="vertical">
+        <Form form={form} layout="vertical" className="mt-4">
           <Form.Item name="display_name" label="显示名">
             <Input />
           </Form.Item>