Remote session UI does not render on GitHub Mobile app (Android) - WebSocket works but content not displayed

## Bug Description

On Android (Google Pixel 6a, Android stock), the GitHub Mobile app receives remote CLI session data (push notifications work) but the UI does not render the session content. Only a static `confirm working functionality` text is shown with a colored status indicator.

## Environment

- **Device**: Google Pixel 6a
- **OS**: Android (stock, latest)
- **GitHub Mobile app**: latest version (cache cleared, force-stopped and relaunched)
- **Copilot CLI version**: latest
- **Session type**: tmux persistent session launched with `copilot --continue`

## Steps to Reproduce

1. Start a Copilot CLI session inside tmux on a Raspberry Pi (ARM64, Ubuntu)
2. Run `/remote` to enable remote control
3. Scan the QR code with GitHub Mobile app on Android Pixel 6a
4. Observe: app shows the session in the Copilot tab with a colored status indicator and `confirm working functionality` text
5. Type a message in the app → no response displayed in the UI
6. Push notifications ARE received (audio notification plays) confirming the WebSocket connection is alive

## Expected Behavior

Session content should render in real-time in the GitHub Mobile app, mirroring the CLI session.

## Actual Behavior

- UI is frozen on `confirm working functionality`
- Notifications are received (WebSocket is working)
- No session content rendered
- Toggling `/remote off` then `/remote on` does not fix the issue
- Clearing app cache does not fix the issue

## Workaround

Using the browser (mobile Chrome or desktop) at https://github.com/copilot works correctly — session renders in real-time with no issues.

## Additional Notes

This appears to be a UI rendering bug rather than a connectivity issue, since the WebSocket is clearly functional (notifications arrive). The browser implementation works perfectly on the same network/device.

No repository file or test is identified. Start by reproducing the issue through the GitHub Mobile Copilot tab after enabling `/remote`, then compare the mobile rendering path with the working browser session and verify that session content appears instead of the static text.

索引モデルが issue の本文から書いたものです。