When starting Mayor via 'gt may at', the session now:
1. Works from townRoot (~/gt) instead of mayorDir (~/gt/mayor)
2. Includes startup beacon with explicit instructions in initial prompt
3. Removes redundant post-start nudges (beacon has instructions)
This matches the 'gt handoff' behavior where the agent immediately
knows to check hook and mail on startup.
Fixes: hq-h3449 (P0 escalation - horrendous starting UX)
Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>