use eslint 9 and update tmp package

[manuelpuyol]

Updating dependencies to close security vulnerabilities

[Copilot]

Pull Request Overview

Updates the project to use ESLint 9 with flat configuration and upgrades dependencies to address security vulnerabilities. The changes modernize the linting setup while maintaining the same code quality rules.

• Migrated from ESLint 6 to ESLint 9 with flat configuration format
• Updated multiple ESLint-related packages to their latest versions
• Added trailing commas to improve code consistency

Reviewed Changes

Copilot reviewed 5 out of 6 changed files in this pull request and generated 3 comments.

Show a summary per file

File	Description
package.json	Updated ESLint and related dependencies, removed old config, added lint:fix script
eslint.config.mjs	New flat ESLint configuration replacing old package.json config
vitest.config.ts	Added trailing comma for consistency
index.ts	Added trailing comma for consistency
test/index.ts	Reformatted function and renamed variables for consistency

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