This commit integrates `remark-lint-no-dead-urls` into the project's
linting process, improving documentation quality by checking for dead
links.
Key changes:
- Add NPM command to verify external URLs in markdown files
- Include new command in the main lint script
Other supporting changes:
- Replace archive.ph link with Wayback Machine for better verification
- Update `remark-lint-no-dead-urls` to latest version (2.0.0)
- Update Browserslist DB to latest to avoid build errors
4e06d543b3