type PartialLevel = 10 | 20 | 30 | 40 | 50 | 60 | 70 | 80 | 90 | 100;
Profit or loss level milestone in percentage points. Represents 10%, 20%, 30%, ..., 100% profit or loss thresholds.
Used to track when a signal reaches specific profit/loss milestones. Each level is emitted only once per signal (deduplication via Set).