TariffPlan.arbitrage(now=...) drops the points whose period has ended
(end <= now), so the cheapest and dearest point can still be traded.
decide() (modes off), the modes-on allowed() gate and the Home verdict
all pass their own now. Hourly feeds and the static tariff are unchanged.
The off-peak sentence and the charge/discharge sentences say "price
period". Tests: test_price02.py; test_arbitrage.py rolls its whole-day
plans to start at now; test_modes_p3.py part 1 digests leave the trade
sentence out (commands unchanged on 7a00f12, 90bc901 and this tree).
Co-Authored-By: Claude <noreply@anthropic.com>
