Detect Storage Gaps Misconfiguration

# 🧠 Concept  
Detect incorrect upgradeable storage gap usage.

## ⚠️ Problem  
Improper storage gaps may break upgradeability.

## 📁 Implementation Scope  
- `rules/security/storage-layout/`

## ✅ Requirements  
- Validate storage gap declarations  
- Detect overlaps  

## 🎯 Acceptance Criteria  
- [ ] Misconfigured storage gaps flagged  