Sessions without summary header don't appear in /resume picker

Description

Some sessions are saved without a proper "type": "summary" header as the first line of the .jsonl file. These sessions don't appear in the /resume or claude --resume picker, even though they contain valid conversation data.

Steps to reproduce

1. Start a Claude Code session
2. Have a conversation
3. Exit and run claude --resume
4. Some sessions may not appear in the list

Expected behavior

All saved sessions should appear in the resume picker.

Actual behavior

Sessions where the first line is "type": "file-history-snapshot" instead of "type": "summary" are not shown in the picker.

Evidence

Session file 5ebc9d63-851f-4b0c-b97a-37325bdcd01a.jsonl (286KB, valid content) starts with:

{"type": "file-history-snapshot", ...}

While working sessions start with:

{"type": "summary", "summary": "...", ...}

Environment

• Claude Code version: 2.0.76
• OS: Debian Linux 6.1.0-41-amd64
• Terminal + CLion IDE integration