Unsent composer text is discarded when the app prompts for re-login

### Preflight Checklist

- [x] I have searched [existing issues](https://github.com/anthropics/claude-code/issues?q=is%3Aissue%20state%3Aopen%20label%3Abug) and this hasn't been reported yet
- [x] This is a single bug report (please file separate reports for different bugs)
- [x] I am using the latest version of Claude Code

### What's Wrong?

While typing a long message in the composer, the app prompted me to
re-authenticate. After signing back in, the text I had typed was gone.

The conversation transcript itself was intact — only the unsent draft
was lost.

I searched the local app state afterwards and the draft is not
persisted anywhere:

- %APPDATA%\Claude\claude-code-sessions\<...>\local_*.json (only session metadata)
- %APPDATA%\Claude\Local Storage\leveldb
- %APPDATA%\Claude\IndexedDB
- %APPDATA%\Claude\Session Storage
- %USERPROFILE%\.claude\projects\\.jsonl (only sent messages)

A re-login prompt is a predictable, app-initiated interruption, not a
crash. The composer draft should be saved before the app interrupts the
session, and restored afterwards.

### What Should Happen?

1. Open the Claude Code desktop app on Windows
2. Start typing a long message in the composer; do not send it
3. Wait for the app to prompt for re-authentication
4. Sign in again
5. The composer is empty — the typed text is gone

### Error Messages/Logs

```shell
The composer draft is preserved across the re-login prompt and restored
after signing back in.
```

### Steps to Reproduce

Claude Code desktop app (Code tab), Windows 11 Pro 10.0.26200

### Claude Model

None

### Is this a regression?

Yes, this worked in a previous version

### Last Working Version

_No response_

### Claude Code Version

Claude Code desktop app (Code tab), Windows 11 Pro 10.0.26200

### Platform

Anthropic API

### Operating System

macOS

### Terminal/Shell

Terminal.app (macOS)

### Additional Information

_No response_

Start by reproducing in the Claude Code desktop app Code tab: type an unsent composer draft, trigger or wait for re-authentication, then sign back in. Inspect the draft/session persistence paths the report checked, including %APPDATA%\Claude storage and %USERPROFILE%\.claude\projects JSONL data. Done means the unsent composer draft is saved before the re-login interruption and restored after sign-in.

由索引模型根据 Issue 内容生成。