Migrate from .eslintrc.js to eslint.config.js (Flat Config)

[Jagoda11]

Hi 👋

While checking out the project, I noticed that the ESLint setup still uses the older .eslintrc.js format.

Would you be open to migrating to the newer eslint.config.js (Flat Config) format? This is now ESLint’s recommended standard and would allow consumer projects that reuse this config to more easily upgrade their tooling and stay current with ESLint's latest practices.

All linting behavior could remain the same—this would just be a structural update.

I'd be happy to submit a PR if you're open to it!

Thanks!