Migrate ESLint to Flat Config (v9+) for TypeScript setup

[revaarathore11]

We are currently using the legacy .eslintrc configuration format.
However, ESLint has introduced the Flat Config system as the new standard starting from v9+

Goal:
Migrate the project’s ESLint setup to Flat Config with proper TypeScript support for better performance, maintainability, and future compatibility.

[revaarathore11]

@uniqueg @anuragxxd I'm working on this please assign me