Support diagnostic with ESlint

[pearmini]

close #118

@jackbdu Use CodeMirror built-in linter to support diagnostic with ESlint:

• https://codemirror.net/examples/lint/
• https://github.com/UziTech/eslint-linter-browserify/blob/master/example/script.js

[Copilot]

Pull Request Overview

This PR integrates ESLint diagnostics into the CodeMirror editor to provide real-time linting feedback, addressing issue #118. The implementation uses CodeMirror's built-in linter system with eslint-linter-browserify to enable client-side JavaScript linting.

• Added ESLint linting support using CodeMirror's linter extension
• Configured ESLint with browser globals and ES2022 module support
• Added necessary dependencies for linting functionality

Reviewed Changes

Copilot reviewed 2 out of 3 changed files in this pull request and generated 2 comments.

File	Description
package.json	Added dependencies for CodeMirror lint extension and ESLint browser support
editor/index.js	Integrated ESLint linter with CodeMirror editor configuration

Files not reviewed (1)

• pnpm-lock.yaml: Language not supported

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