SessionStart hook target that auto-updates gstack at session start.
Background fork (zero latency), throttled to once/hour, with lockfile
(mkdir + PID), stale lock recovery, GIT_TERMINAL_PROMPT=0, and debug
logging to ~/.gstack/analytics/session-update.log.
Part of team-install-mode feature (credit: Jared Friedman).
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
Garry Tan