- Updated sidebar positions across multiple documentation files for improved navigation and logical grouping.
- Revised HAProxy stats configuration to require `HAPROXY_PASSWORD` for enabling statistics.
- Clarified environment variable descriptions and usage in `environment-variable.md`.
- Introduced environment variable support in documentation for Cloudflare, Cleanup, Deny Pages, IP Whitelist, JWT Validator, and FastCGI plugins.
- Updated plugin files with consistent headings, examples, and tables for easier configuration reference.
- Adjusted `README.md` and `plugins.md` to reflect updated plugin paths and environment variable usage.
