feat: migrate ESLint to v9 flat config

- Replace .eslintrc.json with eslint.config.mjs
- Simplify configuration using @antfu/eslint-config
- Add necessary ESLint plugin dependencies
- Disable overly strict style rules
- Set package.json type to module for ESM support
- Fix ESLint disable comment format

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <noreply@anthropic.com>

app/components/base/button/index.tsx

@@ -2,7 +2,7 @@ import type { FC, MouseEventHandler } from 'react'
 import React from 'react'
 import Spinner from '@/app/components/base/spinner'
 
-export type IButtonProps = {
+export interface IButtonProps {
   type?: string
   className?: string
   disabled?: boolean