refactor(prompts): upgrade to v6.0.0 with enhanced safety rules (NoFxAiOS#712)

## 🎯 Motivation

Based on extensive production usage and user feedback, we've developed a more comprehensive prompt system with:
- Stronger risk management rules
- Better handling of partial_close and update_stop_loss
- Multiple strategy templates for different risk profiles
- Enhanced decision quality and consistency

## 📊 What's Changed

### 1. Prompt System v6.0.0

All prompts now follow a standardized format with:
- **Version header**: Clear versioning (v6.0.0)
- **Strategy positioning**: Conservative/Moderate/Relaxed/Altcoin
- **Core parameters**: Confidence thresholds, cooldown periods, BTC confirmation requirements
- **Unified structure**: Consistent across all templates

### 2. New Strategy Templates

Added two new templates to cover different trading scenarios:

- `adaptive_altcoin.txt` - Optimized for altcoin trading
  - Higher leverage limits (10x-15x)
  - More aggressive position sizing
  - Faster decision cycles

- `adaptive_moderate.txt` - Balanced strategy
  - Medium risk tolerance
  - Flexible BTC confirmation
  - Suitable for most traders

### 3. Enhanced Safety Rules

#### partial_close Safety (Addresses NoFxAiOS#301)
```
⚠️ Mandatory Check:
- Before partial_close, calculate: remaining_value = current_value × (1 - close_percentage/100)
- If remaining_value ≤ $10 → Must use close_long/close_short instead
- Prevents "Order must have minimum value of $10" exchange errors
```

#### update_stop_loss Threshold Rules
```
⚠️ Strict Rules:
- Profit <3% → FORBIDDEN to move stop-loss (avoid premature trailing)
- Profit 3-5% → Can move to breakeven
- Profit ≥10% → Can move to entry +5% (lock partial profit)
```

#### TP/SL Restoration After partial_close
```
⚠️ Important:
- Exchanges auto-cancel TP/SL orders when position size changes
- Must provide new_stop_loss + new_take_profit with partial_close
- Otherwise remaining position has NO protection (liquidation risk)
```

### 4. Files Changed

- `prompts/adaptive.txt` - Conservative strategy (v6.0.0)
- `prompts/adaptive_relaxed.txt` - Relaxed strategy (v6.0.0)
- `prompts/adaptive_altcoin.txt` - NEW: Altcoin-optimized strategy
- `prompts/adaptive_moderate.txt` - NEW: Balanced strategy

## 🔗 Related Issues

- Closes NoFxAiOS#301 (Prompt layer safety rules)
- Related to NoFxAiOS#418 (Same validation issue)
- Complements PR NoFxAiOS#415 (Backend implementation)

## ✅ Testing

- [x] All 4 templates follow v6.0.0 format
- [x] partial_close safety rules included
- [x] update_stop_loss threshold rules included
- [x] TP/SL restoration warnings included
- [x] Strategy-specific parameters validated

## 📝 Notes

This PR focuses on **prompt layer enhancements only**.

Backend safety checks (trader/auto_trader.go) will be submitted in a separate PR for easier review.

The two PRs can be merged independently or together - they complement each other:
- This PR: AI makes better decisions (prevent bad actions)
- Next PR: Backend validates and auto-corrects (safety net)

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Co-authored-by: Claude <noreply@anthropic.com>

Author: 2 people