Furnace

This adds a time-based processing route alongside crafting; ore-to-ingot and food cooking consume fuel and need an output plan.

When it fits: Build it when the selected project needs smelting or cooking rather than assuming a crafting recipe covers processing.

The tradeoff: One source recipe run makes 1 and lists 8 Cobblestone at Crafting table; 1 recipe variant(s) for this output are grouped together. Verify access where the pack is incomplete. The furnace recipe is a single station; fuel, batch input and completion time are separate operating needs.