Session open: a random 0–180 minute delay, kept across restarts

The day's delay was 1–20 minutes. It is now 0–180, so the evening open
lands anywhere from 5:05 to 8:05 PM CT. The day's roll is saved as a
setting: with a three-hour window, a restart during the wait (an update, a
crash) would otherwise roll again and could start the session early.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

lib/trading-logic.ts

@@ -1559,7 +1559,7 @@ function centralClock(now: Date): { day: string; minutes: number; resetMinutes:
  * CME firms follow the trading_hours setting:
  *   "full_cme"     — Sun 5:05 PM – Fri 2:55 PM Central (5 min buffer on each side)
  *   "equity_hours" — 8:35 AM – 2:55 PM Central, Mon–Fri (5 min buffer on each side)
- * with the open pushed back by the day's 1–20 minute jitter.
+ * with the open pushed back by the day's 0–180 minute delay.
  *
  * Every-day firms ignore trading_hours and close only around the day's roll:
  * from 5 minutes before the earlier of their 22:00 UTC reset and 5 PM CT, to