New outputSessionMetadata() function prints a structured line at prime start:
[GAS TOWN] role:mayor pid:12345 session:abc-uuid-123
This enables gt seance to discover sessions from Claude transcripts,
complementing the existing event emission to .events.jsonl.
🤖 Generated with [Claude Code](https://claude.com/claude-code)
Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>