Forage Wagon Hay Lock

This script prevents hay already collected in a forage wagon from being overwritten by grass or by another hay type.

Behaviour:

• More of the same hay type collects normally.
• Normal grass is ignored while hay is loaded.
• Fresh clover and fresh alfalfa are ignored while hay is loaded (when those fill types exist).
• A different hay type is ignored while hay is loaded.
• Empty wagons and wagons containing non-hay material retain normal game behaviour.

Supported Hay Types:

• Hay: DRYGRASS_WINDROW
• Clover Hay: DRYCLOVER_WINDROW
• Alfalfa Hay: DRYALFALFA_WINDROW