resume from a session will send 'auto' as a model name in the request

[yahayao]

Description

If you use auto mode in a session to let TUI automatically select a model, and then restart TUI to resume the previous session for dialogue, it will return Warn Invalid request (400): {"error":{"message":"The supported API model names are deepseek-v4-pro or deepseek-v4-flash, but you passed auto.","type":"invalid_request_error","param":null,"code":"invalid_request_error"}}

Steps to reproduce

1. open deepseek-TUI
2. use /model auto change to auto select mode
3. use /exit quit TUI
4. reopen deepseek and have a conversation

Expected behavior

api can return normal response

Actual behavior

api return invalid request warning

Environment

• OS: Win 10
• DeepSeek CLI version: 0.8.38
• Install method: npm
• Model/provider: deepseek
• Terminal app: Windows Terminal
• Shell: powershell