- Add KuCoin-specific balance fetching with type='trade' parameter
- Reinitialize ccxt client in refresh_balances() to fix pickle corruption
- Force reconnection when exchange is restored from database cache
- Add balance refresh button and socket handler in frontend
- Fix template null check for balances display
- Clean up DataCache and candles imports
Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>