Merge pull request #7 from cusaldmsr/Dev

Refactor README.md for clarity and structure; update features, technologies, and usage instructions

Implement Singleton pattern and safe parsing in Calculator class

Implement Singleton pattern and safe parsing in Calculator class

Update README.md

Update README.md

Update Readme.md

Update Resources

Update README.md

Rename profile-pic (2).png to cusaldmzr.png

Add files via upload

Create SECURITY.md

Update README.md

add image files

Update README.md