CRITICAL FIX: TP/SL orders using wrong size calculation

**ROOT CAUSE:** placeExitOrders() calculated position size using TP/SL prices instead of entry price

**Problem:**
- TP1 order size: 85 / TP1_price (00.746) = 2.914 SOL
- Actual position: 80 / entry_price (99.946) = 3.901 SOL
- TP1 should close: 3.901 * 75% = 2.926 SOL
- But it only closed: 2.914 SOL = 74.7% ❌ WRONG!

**Result:** TP1 closed ~25% instead of 75%, no runner left

**Fix:**
- Changed usdToBase() to use entryPrice for ALL size calculations
- Added entryPrice param to PlaceExitOrdersOptions interface
- Updated all API routes to pass entryPrice

**Testing:** Next trade will have correctly sized TP/SL orders

.env

@@ -61,7 +61,7 @@ PYTH_HERMES_URL=https://hermes.pyth.network
 # Position sizing
 # Base position size in USD (default: 50 for safe testing)
 # Example: 50 with 10x leverage = $500 notional position
-MAX_POSITION_SIZE_USD=78
+MAX_POSITION_SIZE_USD=54
 
 # Leverage multiplier (1-20, default: 10)
 # Higher leverage = bigger gains AND bigger losses