docs: Add Pyramiding/Position Stacking implementation plan

- Create comprehensive PYRAMIDING_IMPLEMENTATION_PLAN.md with:
  - Data-driven justification (100% WR for signals ≤72 bars apart)
  - User-selected parameters (4h window, 7x→14x leverage)
  - ENV variables, database schema, execute endpoint logic
  - Position manager updates, Telegram notifications
  - 7-phase implementation checklist
  - 4 expected behavior examples

- Add reference in copilot-instructions.md under Development Roadmap
  - Documents planned pyramiding system
  - Links to implementation plan for future agent

.github/copilot-instructions.md

@@ -5947,6 +5947,78 @@ All technical improvements must align with current phase objectives (see top of
 - Comparison with executed trades at similar quality levels
 - Future automation of price tracking (would TP1/TP2/SL have hit?)
 
+---
+
+## 🔺 Pyramiding/Position Stacking System (Jan 6, 2026 - PLANNED)
+
+**Status:** 📋 PLANNED - Implementation plan ready, awaiting development
+
+**Purpose:** Scale into winning positions by adding to existing trades when confirmation signals arrive within a time window. Based on ML v11.2 backtesting analysis showing 100% win rate for signals ≤72 bars apart.
+
+**Implementation Plan:** See `docs/PYRAMIDING_IMPLEMENTATION_PLAN.md` for complete details
+
+**Key Parameters (User-Selected):**
+- **Stacking Window:** 4 hours (240 minutes / 48 bars on 5-min chart)
+- **Base Leverage:** 7x (first entry)
+- **Stack Leverage:** 7x (additional entry)
+- **Max Total Leverage:** 14x (7x + 7x = 2 pyramid levels)
+- **Max Pyramid Levels:** 2 (base + 1 stack)
+
+**Data-Driven Justification:**
+- Backtesting analysis of ML v11.2 pyramiding trades
+- **≤72 bars (6 hours):** 100% win rate - signals close together confirm trend
+- **>72 bars:** 67.6% win rate - too far apart, trend may have reversed
+- User chose conservative 48-bar (4-hour) window for production
+
+**Environment Variables (New):**
+```bash
+ENABLE_PYRAMIDING=true
+BASE_LEVERAGE=7
+STACK_LEVERAGE=7
+MAX_LEVERAGE_TOTAL=14
+MAX_PYRAMID_LEVELS=2
+STACKING_WINDOW_MINUTES=240
+```
+
+**Database Schema Changes:**
+```prisma
+model Trade {
+  // ... existing fields
+  pyramidLevel        Int?      // 1 = base, 2 = first stack, etc.
+  parentTradeId       String?   // Links stacked trades to base
+  stackedAt           DateTime? // When stack was added
+  totalLeverageAtEntry Float?   // Running total leverage
+  isStackedPosition   Boolean   @default(false)
+}
+```
+
+**Core Logic:**
+1. First signal → Open position with 7x leverage (pyramidLevel: 1)
+2. Second signal within 4 hours → Check if same direction + within window
+3. If valid → Add 7x position (pyramidLevel: 2), total leverage now 14x
+4. Position Manager tracks both as linked positions
+5. Exit → Close ALL pyramid levels together (unified exit)
+
+**Safety Checks:**
+- ✅ Same direction only (no hedging)
+- ✅ Within stacking window (4 hours default)
+- ✅ Max leverage cap (14x)
+- ✅ Max pyramid levels (2)
+- ✅ Sufficient free collateral for additional position
+
+**TradingView Strategy (Already Implemented):**
+- File: `workflows/trading/moneyline_v11_2_strategy.pinescript`
+- Has pyramiding=1 setting and barSpacingThreshold input
+- Debug table shows bar spacing and stacking decisions
+
+**References:**
+- Implementation plan: `docs/PYRAMIDING_IMPLEMENTATION_PLAN.md`
+- TradingView strategy: `workflows/trading/moneyline_v11_2_strategy.pinescript`
+- Backtesting data: `backtester/dynamic_threshold_backtest_20251223_152614.csv`
+- Analysis document: `V11_COMPREHENSIVE_ANALYSIS_DEC17_2025.md`
+
+---
+
 ## Telegram Notifications (Nov 16, 2025 - Enhanced Nov 20, 2025)
 
 **Position Closure Notifications:** System sends direct Telegram messages for all position closures via `lib/notifications/telegram.ts`