[Feature Request] Expose live conversation summary programmatically

Problem

Claude Code generates and updates a conversation summary in real-time, visible in the terminal tab title.

However, this live summary is not accessible programmatically:

• The JSONL conversation file only receives a summary entry when the conversation ends (and this may be a different summary, generated separately)
• During an active session, there's no {"type":"summary",...} entry in the conversation file
• Status line hooks receive transcript_path but not the current summary

Proposed Solutions

Any of these would help:

1. Status line hook: Include a summary field in the JSON passed to status line hooks
2. Periodic writes: Write summary updates to the JSONL file during the conversation (not just at end)
3. CLI query: Provide a flag like claude --get-summary <session-id> to retrieve the current summary