Update HTML files and asset paths for model-leaderboard-fork structure

- Updated DOCTYPE comments and asset paths in multiple HTML files to reflect the new model-leaderboard-fork directory structure.
- Modified metadata in various pages to enhance SEO and ensure proper formatting in index.txt files.
- Introduced new JavaScript chunks and build manifests to improve performance and modularity.
- Updated references in the PCS, FAQ, and methodology sections to align with the new structure and enhance user experience.
- Removed outdated CSS files and adjusted the Next.js configuration for streamlined asset management.

Author: isoceles