Conversation history shows /clear as title instead of first user message

Description

When using the /clear command in Claude Code CLI, the resulting conversation entry in the conversation history (e.g. when browsing past sessions via /resume) is titled /clear instead of the first actual user message that followed it.

Steps to reproduce

1. Start a Claude Code session
2. Run /clear to clear context
3. Send an actual user message (e.g. "help me refactor this function")
4. Exit the session
5. Open conversation history (e.g. /resume)

Expected behavior

The conversation should be titled with the first real user message ("help me refactor this function").

Actual behavior

The conversation is titled /clear, which is uninformative and makes it hard to identify sessions in history.

Suggested fix

Skip slash commands when picking the title for a conversation; use the first non-slash-command user message instead.