Migrate linting and formatting to Ruff (#86)

[BhuwanSKumar]

Summary

This PR migrates the project from flake8 + isort + mypy to Ruff for linting, formatting, and import sorting.

Changes

• Added Ruff configuration in pyproject.toml.
• Updated tox.ini to run Ruff instead of flake8/isort/mypy.
• Replaced linting dependencies in requirements.txt with Ruff.
• Reformatted all Python files using Ruff.

Benefits

• Much faster linting (~50-200ms per run).
• Consolidates linting, import sorting, and formatting into a single tool.
• Modern Python syntax checks included.
• Simplifies CI/CD integration and developer setup.

Closes Issue #86

[Elnaril]

Hi @BhuwanSKumar !
Are you working on this for Hacktoberfest ? Asking because I haven't flagged it as such and, more importantly, I have not given a lot of thought about it, so the requirements lack details. And I'm not even sure that Ruff does what I want and how I want ...

Just out of my head:

• Ruff would replace flake8 and isort, but not mypy
• The code should not be changed because of this PR, except where expected or duly justified

If it turned out that Ruff does not satisfy my vision, I may just dismiss it ...