Detect Overly Complex Functions

# 🧠 Concept  
Identify functions with excessive complexity.

## ⚠️ Problem  
Complex functions reduce readability and auditability.

## 📁 Implementation Scope  
- `src/analysis/complexity/`

## ✅ Requirements  
- Compute cyclomatic complexity  
- Flag large functions  

## 🎯 Acceptance Criteria  
- [ ] Complex functions identified  