Fix exchange order double-counting in financial log

[TaprootFreak]

Summary

• Fixes double-counting of exchange order inputAmount in saveTradingLog() when funds arrive at the destination exchange before the order is marked complete
• For transfer/deposit commands between exchanges, the destination balance (updated via WebSocket/API) already includes the transferred funds, but the IN_PROGRESS order's inputAmount was also added — causing alternating valid/invalid log entries
• Now only counts exchangeOrder when action.system matches the target asset's exchange (funds leaving this exchange), skipping when funds arrive from another exchange

Root cause

When a transfer order moves funds from exchange A to exchange B (e.g. Kraken → Scrypt):

1. action.system = source exchange (Kraken)
2. targetAsset = managed asset on destination (Scrypt/USDT)
3. Scrypt balance updates immediately (WebSocket subscription)
4. Order stays IN_PROGRESS until deposit confirmed in Scrypt's deposit list
5. saveTradingLog counts both liquidity (updated balance) and exchangeOrder (pending order) → double-count

Test plan

• Verify financial log entries no longer alternate between valid/invalid
• Verify Scrypt/USDT exchangeOrder is 0 when transfer order has already been reflected in balance
• Verify withdrawal orders (exchange → blockchain) still correctly compensate for decreased exchange balance
• Verify redundancy transfer orders (funds leaving target exchange) are still counted