Loading Wagon Hay Lock

PURPOSE
Prevents hay already collected in a loading wagon from being overwritten by grass or another type of hay.

BEHAVIOR
– Additional amounts of the same hay type are picked up normally.
– Regular grass is ignored while hay is being loaded.
– Fresh clover and fresh alfalfa are ignored while hay is being loaded (if these fill types exist).
– A different hay type is ignored while hay is being loaded.
– Empty wagons and wagons containing non-hay material retain normal game behavior.

SUPPORTED HAY TYPES
– Hay: DRYGRASS_WINDROW
– Clover hay: DRYCLOVER_WINDROW
– Alfalfa hay: DRYALFALFA_WINDROW

Supports grass, hay, as well as registered windrow variants of clover and alfalfa. The first picked-up hay type remains locked until the wagon is emptied. Matching material can still be picked up, while incompatible grass/hay stays on the ground.