Large furnace stops when charcoal output slot reaches stack limit (5k)

Hey Shady14u! Reporting a bug found by players on our PVE x2 server.

When using a large furnace, charcoal output is not distributed across multiple output slots — it always accumulates in the first output slot only. Once that slot reaches the 5k stack limit, the furnace stops completely, even with "Ignore Stack Limit In Smelted Output Slots" set to true.

This setting seems to apply correctly to smelted ore slots, but not to the charcoal output slot.

Steps to reproduce:
1. Place a large furnace
2. Load wood as fuel
3. Let it run until charcoal output reaches 5000
4. Furnace stops — charcoal is only in slot 0, other output slots are empty

Expected behavior: charcoal should either distribute across available output slots, or "Ignore Stack Limit" should also apply to the charcoal slot so the furnace doesn't stop.

Thanks for the great plugin and for keeping it maintained!