Farmer's Delight: Contracts & Feasts

Fixed:

Contract board GUI could leak a live ItemStack reference into a player's inventory (via the number-key hotbar-swap click) instead of a copy, letting the shared board contract get corrupted/aliased with a player's item.
/time set and /time add could force an instant board refill on demand (bypassing the intended multi-day refresh cadence), since day tracking read getDayTime() directly. Switched to the monotonic tick counter plus a sleep-skip offset, so sleeping through the night still works correctly and the commands no longer do anything to the board.
A contract with two objective lines on the same item (a real case the generator can produce) could be turned in for less than the true combined amount required, due to checking/consuming each line independently instead of merged by item.
The board menu never closed automatically when the player walked away or the block was destroyed while the GUI was open.