Add copper furnace

Update

1. Added copper furnace, which can be used to make silver ingots and gold ingots.

2. Add recipes for silver weapons and silver equipment.

3. Add recipes for gold weapons and gold equipment.

4. Modify the display of damage numbers.

5. Add critical hit damage.

6. Add monster armor damage reduction.

7. Add the judgment of digging force.

8. Add special effects of broken ground.