RFC: ESLint 9 Migration – Transitioning from JSON Config to config.js

### Description

**Summary**

This RFC proposes migrating the ESLint configuration from the deprecated .eslintrc.* format to the new eslint.config.js format introduced in ESLint 9. Additionally, it outlines handling the removal of .eslintignore in favor of the ignores property inside the configuration file.

**Expected Outcomes**
- Successful Migration to eslint.config.js – Ensures compatibility with ESLint 9.
- Removal of Deprecated Configurations – .eslintrc.* and .eslintignore are replaced with eslint.config.js.
- Consistent and Maintainable Linting Rules – The same linting standards are preserved.

### Related Issues

_No response_

### Questions

No.

### Other

No.

### Checklist

- [x] I have read and understood the [Code of Conduct](https://github.com/stdlib-js/stdlib/blob/develop/CODE_OF_CONDUCT.md).
- [x] Searched for existing issues and pull requests.
- [x] The issue name begins with `RFC:`.

Start by locating the repository's .eslintrc.* files and .eslintignore, then review the existing linting rules and how ESLint is invoked. Done means replacing the deprecated configuration with eslint.config.js, moving ignore patterns into its ignores property, preserving the current standards, and confirming ESLint 9 compatibility.

Written by the indexing model from the issue text.