Setup GitHub Actions CI pipeline

### 🧩 Module

CI/CD Pipeline

### 📝 Description

Runs tests and upload reports as artifact

### ✅ Tasks

```markdown
- Trigger on PR & push or manual (preferred)
- Lint + unit test both backend & frontend
- Upload coverage report as artifact
```

### 🔥 Priority

High

### 💬 Additional Notes

_No response_