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/AgentTemplates.tsx

@@ -4,8 +4,8 @@
 
 import { useState } from 'react'
 import { useQuery, useMutation, useQueryClient } from '@tanstack/react-query'
-import { Button, message, Tag, Modal, Form, Input, Select, InputNumber, Space, Popconfirm, Descriptions, MinusCircleOutlined } from 'antd'
-import { PlusOutlined } from '@ant-design/icons'
+import { Button, message, Tag, Modal, Form, Input, Select, InputNumber, Space, Popconfirm, Descriptions } from 'antd'
+import { PlusOutlined, MinusCircleOutlined } from '@ant-design/icons'
 import type { ProColumns } from '@ant-design/pro-components'
 import { ProTable } from '@ant-design/pro-components'
 import { agentTemplateService } from '@/services/agent-templates'