Add v7-momentum indicator (experimental, disabled)

- Created momentum scalper indicator for catching rapid price acceleration
- ROC-based detection: 2.0% threshold over 5 bars
- Volume confirmation: 2.0x spike (checks last 3 bars)
- ADX filter: Requires 12+ minimum directional movement
- Anti-chop filter: Blocks signals in dead markets
- Debug table: Real-time metric display for troubleshooting

Status: Functional but signal quality inferior to v6 HalfTrend
Decision: Shelved for now, continue with proven v6 strategy
File: docs/guides/MOMENTUM_INDICATOR_V1.pine (239 lines)

Lessons learned:
- Momentum indicators inherently noisy (40-50% WR expected)
- Signals either too early (false breakouts) or too late (miss move)
- Volume spike timing issue: Often lags price move by 1-2 bars
- Better to optimize proven strategy than add complexity

Related: Position Manager duplicate update bug fixed (awaiting verification)

lib/trading/position-manager.ts

@@ -488,8 +488,24 @@ export class PositionManager {
           // else: small profit/loss near breakeven, default to SL (could be manual close)
         }
         
-        // Update database
+        // Update database - CRITICAL: Only update once per trade!
         const holdTimeSeconds = Math.floor((Date.now() - trade.entryTime) / 1000)
+        
+        // CRITICAL BUG FIX: Mark trade as processed IMMEDIATELY to prevent duplicate updates
+        // Remove from monitoring BEFORE database update to prevent race condition
+        const tradeId = trade.id
+        
+        // VERIFICATION: Check if already removed (would indicate duplicate processing attempt)
+        if (!this.activeTrades.has(tradeId)) {
+          console.log(`⚠️ DUPLICATE PROCESSING PREVENTED: Trade ${tradeId} already removed from monitoring`)
+          console.log(`   This is the bug fix working - without it, we'd update DB again with compounded P&L`)
+          return // Already processed, don't update DB again
+        }
+        
+        this.activeTrades.delete(tradeId)
+        console.log(`🗑️ Removed trade ${tradeId} from monitoring (BEFORE DB update to prevent duplicates)`)
+        console.log(`   Active trades remaining: ${this.activeTrades.size}`)
+        
         try {
           await updateTradeExit({
             positionId: trade.positionId,
@@ -510,8 +526,11 @@ export class PositionManager {
           console.error('❌ Failed to save external closure:', dbError)
         }
         
-        // Remove from monitoring
-        await this.removeTrade(trade.id)
+        // Stop monitoring if no more trades
+        if (this.activeTrades.size === 0 && this.isMonitoring) {
+          this.stopMonitoring()
+        }
+        
         return
       }