`/desktop` fails with "CLI session transcript not found" when run as the first command in a session

Bug description

Running /desktop to migrate a session to the Claude Code desktop app fails when it is the first command in a fresh session (before any turn has been written). The desktop app shows:

CLI session transcript not found: 7f6698ae-8a22-4142-a948-248fe8f56982

Steps to reproduce (minimal)

1. Start a new Claude Code session
2. As the very first input, run /desktop
3. Desktop app errors: CLI session transcript not found: <session-id>

Running /desktop after the session has at least one turn works fine.

Diagnostic

On an empty session, no transcript .jsonl has been flushed to disk yet, so the session ID /desktop hands to the app doesn't resolve to any file. Confirmed for the failing ID:

$ find ~/.claude -name "7f6698ae-8a22-4142-a948-248fe8f56982*"
(no results)

while a session with at least one turn has its transcript present under the project dir (e.g. ~/.claude/projects/<encoded-cwd>/<session-id>.jsonl).

Expected behavior

/desktop either flushes/creates the transcript before handoff, or the desktop app handles a not-yet-written transcript gracefully (wait/retry, or an actionable message) instead of failing with "transcript not found".

Environment

• Claude Code 2.1.150
• macOS 15.7.4 (24G517), Apple Silicon

Notes

• Originally observed in a git worktree created by a custom hook (repo also uses git separate-git-dir), but the worktree setup turned out to be incidental — the real condition is "/desktop invoked before any transcript exists on disk."