Balance notes: whole-number gold, replay fatigue

Battle gold is now whole numbers at a ×10 scale; replaying old battles gives diminishing gold.

• Battle gold is whole numbers at a ×10 scale (existing gold was multiplied too, nobody lost value).
• Replaying old battles gives full gold for the first wins of the day, then less.
• Old battles have a daily Seal cap; new battles always give Seals.