critical: Fix breakeven SL using wrong entry price after TP1

- CRITICAL BUG: Drift SDK's position.entryPrice RECALCULATES after partial closes
- After TP1, Drift returns COST BASIS of remaining position, NOT original entry
- Example: SHORT @ 38.52 → TP1 @ 70% → Drift shows entry 40.01 (runner's basis)
- Result: Breakeven SL set .50 ABOVE actual entry = guaranteed loss if triggered

Fix:
- Always use database trade.entryPrice for breakeven calculations
- Drift's position.entryPrice = current state (runner cost basis)
- Database entryPrice = original entry (authoritative for breakeven)
- Added logging to show both values for verification

Impact:
- Every TP1 → breakeven transition was using WRONG price
- Locking in losses instead of true breakeven protection
- Financial loss bug affecting every trade with TP1

Files:
- lib/trading/position-manager.ts: Line 513 - use trade.entryPrice not position.entryPrice
- .github/copilot-instructions.md: Added Common Pitfall #43, deprecated old #44

Incident: Nov 16, 02:47 CET - SHORT entry 38.52, breakeven SL set at 40.01
Position closed by ghost detection before SL could trigger (lucky)

.env

@@ -376,7 +376,7 @@ TRAILING_STOP_ACTIVATION=0.4
 MIN_QUALITY_SCORE=60
 SOLANA_ENABLED=true
 SOLANA_POSITION_SIZE=100
-SOLANA_LEVERAGE=15
+SOLANA_LEVERAGE=10
 SOLANA_USE_PERCENTAGE_SIZE=true
 ETHEREUM_ENABLED=false
 ETHEREUM_POSITION_SIZE=50