Migrate to eslint flat config

[acelaya]

• https://eslint.org/docs/latest/use/configure/migration-guide
• https://eslint.org/docs/latest/extend/plugin-migration-flat-config
• https://eslint.org/docs/latest/use/configure/configuration-files-new

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Dependencies which already support flat config

• @stylistic/eslint-plugin
• typescript-eslint
• eslint-plugin-simple-import-sort
• eslint-plugin-jsx-a11y Add support for ESLint 9 jsx-eslint/eslint-plugin-jsx-a11y#978 (comment)
• eslint-plugin-react https://github.com/jsx-eslint/eslint-plugin-react?tab=readme-ov-file#configuration-new-eslintconfigjs
• eslint-plugin-react-hooks eslint-plugin-react-hooks & "Flat Config" (ESLint 9) facebook/react#28313