[BUG] Sessions with API error summary are hidden from /resume

Preflight Checklist

• [x] I have searched existing issues 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?

Description

Sessions whose summary field contains "API Error" are filtered out from the /resume list.

Important: This is NOT an indexing issue. The session IS correctly present in sessions-index.json with valid data. The problem is a UI filtering that hides sessions based on their summary content.

Proof: Manually editing the summary field in sessions-index.json to remove "API Error" makes the session reappear in /resume immediately.

## Workaround

Manually edit ~/.claude/projects/<project>/sessions-index.json and change the summary field to remove "API Error".

## Impact

During Anthropic outages, users lose access to their work sessions precisely when they need to resume them after service is restored.

What Should Happen?

Sessions interrupted by API errors should appear in /resume like any other session. The error status could be shown as a visual indicator, but the session should remain accessible.

Error Messages/Logs

Steps to Reproduce

1. Start a Claude Code session in a project directory
2. Work on it until an Anthropic API outage occurs (500 error)
3. Wait for the session to terminate with the error
4. Restart Claude Code in the same directory
5. Type /resume
6. Observe that the interrupted session is not listed
7. Check ~/.claude/projects/<project-hash>/sessions-index.json - the session exists with summary "API Error: 500 ..."

Claude Model

Opus

Is this a regression?

Yes, this worked in a previous version

Last Working Version

_No response_

Claude Code Version

2.1.20

Platform

Anthropic API

Operating System

Ubuntu/Debian Linux

Terminal/Shell

Other

Additional Information

I'm using the default Bash terminal of my Ubuntu: GNOME Terminal.