[BUG] Mobile app stays stuck in running state after immediate cancellation, while terminal task continues to completion

### 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?

I was using the Claude mobile app to control an existing Claude Code session running in a terminal on my computer. I sent a task and immediately tapped stop/cancel.

The mobile app remained in a running/processing state, with no progress or response. Its send/stop control continued to indicate that the task was running. In the terminal, the task continued despite the cancellation attempt and ran to completion. The mobile app still appeared to be running after the terminal task had finished.

### What Should Happen?

Cancelling from the app should interrupt the corresponding terminal task. Both interfaces should show the correct status. If cancellation fails or arrives too late, the app should reflect the actual state and show the result rather than remain stuck.

### Error Messages/Logs

```shell

```

### Steps to Reproduce

1. Open an existing Claude Code terminal session in the Claude mobile app.
2. Send a new task from the app.
3. Immediately tap stop/cancel.
4. Compare the mobile app and terminal, including after the terminal task finishes.

These steps describe the observed incident. Reproducibility has not yet been confirmed.

### Claude Model

Opus

### Is this a regression?

I don't know

### Last Working Version

_No response_

### Claude Code Version

1.260902.20 (33711720409)

### Platform

Anthropic API

### Operating System

macOS

### Terminal/Shell

Terminal.app (macOS)

### Additional Information

Immediate cancellation may be relevant; the cause has not been diagnosed. Related reports with different triggers: #32457 and #87313. No logs or screenshots attached yet.

No source file or test is named. Start by reproducing the immediate-cancellation flow between the Claude mobile app and the existing Claude Code terminal session on macOS, then compare the behavior with related reports #32457 and #87313. Done means cancellation interrupts the terminal task when possible, and both interfaces show the final state when it arrives too late.

由索引模型根据 Issue 内容生成。