- platform.sh: nh_ensure_instance/nh_entry_write now use per-SITE instance
  (port 9300+hash(site), profiles/<site>/) so one account logs in once per
  site; prevents same-account multi-login session kicking (digitimes/nikkei
  both enforce device limits)
- harvest.sh: quit shared instance on EXIT with port-keyed reference counting
  ($WORK_DIR/runlocks, stale-PID cleanup) — last same-site run recycles
- harvest.sh: hard watchdog kills a hung claude run after MAX_RUNTIME_MIN
  (default 60, per-source conf overridable) so launchd next-day trigger is
  never blocked