Code Quality and Stability Improvements

[AndrewDongminYoo]

This pull request incorporates multiple fixes, enhancements, and chore tasks to improve the overall quality, stability, and maintainability of the appstore-status-bot project.

Summary of Changes

Bug Fixes

1. Fix Extensions
   Resolved extension issues in the following modules:

   • check_status.js
   • discord.js
   • slack.js

2. Type Conversion
   Addressed type conversion issues in check_status.js.

3. Error Repeating State Change
   Fixed a bug where state changes were incorrectly repeated every 15 minutes (=== comparison error). Affected files:

   • check_status.js
   • discord.js
   • slack.js

4. Module Resolution
   Fixed a "module not found" error in check_status.js.

5. __dirname in ES Modules
   Resolved the issue with __dirname being undefined in the ES module scope. Updated:

   • check_status.js
   • discord.js
   • slack.js

6. Require of ES Module
   Fixed compatibility issues with ES module imports across:

   • check_status.js
   • discord.js
   • slack.js
   • eslint.config.mjs
   • Documentation updates in README.md.

7. Replace node-fetch with axios
   Improved HTTP request handling by migrating from node-fetch to axios in discord.js.

8. Vulnerability Fixes

   • Replaced request package with axios due to vulnerabilities.
   • Fixed vulnerabilities in Gemfile.lock.

Enhancements

1. Environment Shortcut Setup
   Introduced environment variable shortcuts for easier configuration. Added env.js.

2. Node Version Upgrade
   Upgraded Node.js version in .github/workflows/fetch.yml for better performance and compatibility.

Documentation

1. Typos Fixed
   Fixed typos in:

   • README.md
   • README-JAPANESE.md
   • README-KOREAN.md

2. ESLint Installation
   Installed and configured ESLint (eslint.config.mjs) to ensure consistent code quality.

Chores

1. Source Code Formatting
   Reformatted all source files for consistent style:

   • JavaScript files
   • Workflow and documentation files
   • Localization files

2. NPM Type to ES Module
   Updated package.json to properly use ES modules.

3. Workflow Updates
   Fixed workflow file configurations in .github/workflows/fetch.yml and .github/FUNDING.yml.

Additional Changes

1. Added ESLint Configuration
   Integrated ESLint with a new configuration file to enforce code quality standards.

2. Updated Images
   Adjusted GitHub-related images for consistency:

   • og.png
   • preview.png
   • preview_ko.png

Testing and Verification

• Verified all changes locally and in CI/CD pipelines.
• Resolved all previously reported issues and vulnerabilities.

Impact

These changes significantly improve the bot's reliability, maintainability, and adherence to modern development practices.