Add a new "retro" theme option that mimics the classic Windows 98 aesthetic, providing a nostalgic alternative to the modern and classic dark themes.
Changes include:
- Defining CSS variables for the retro theme in `00-base.css` (pixel fonts, silver/gray colors, and classic window shadows).
- Adding custom styling for cards, headers, buttons, and title bars to replicate classic OS windows.
- Adding a star background GIF (`stars1.gif`).
- Excluding the retro theme from modern "revamp" styles in `15-revamp.css`.
- Updating `CLAUDE.md` with instructions on screenshot verification.
Initialize the repository with the core Go backend architecture and a frontend mockup for warpbox.dev, a self-hosted file-sharing application.
- Set up Go backend modules for configuration, HTTP server, middleware, handlers, and templates.
- Add local development scripts, environment templates, and basic project configuration.
- Include a React-based frontend mockup under the docs directory.
