Add integration tests with Terratest

[kogunlowo123]

Description

Currently this module has syntax validation tests but no integration tests that deploy real infrastructure.

What's Needed

• Add Terratest (Go) or pytest-terraform integration tests
• Test basic deployment and destruction
• Validate key outputs match expected values
• Add test documentation to README

Getting Started

1. Fork this repo
2. Create a test/ directory with Go test files
3. Use terratest library
4. Submit a PR

This is a great first contribution!