d8f13d674d
Extract the month-by-month backward-walk algorithm (used for both team-level cash balance and player-level debt history) into a single shared private helper `reconstructBackward()`. This eliminates code duplication while preserving behavior: - Team-level balanceHistory: maps movements through signedFlowAmount(), rounds each point, calls the shared helper - Player-level balance history: maps transactions using type.id rule, skips rounding (only rounds at final merge to avoid compounding errors), calls the shared helper Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>