Add Utumishi static site scaffold (HTML, CSS, README)

[t-mwau]

Motivation

• Provide a responsive static website template for an "Utumishi Archive" to organize journals, books, and materials including layout, styles, and usage guidance.
• Make it easy to add the project into the DecodeLabs-Internship repository with explicit folder structure and setup commands.

Description

• Add utumishi/index.html implementing the homepage with a hero, collections, archive workflow, services, and contact/footer sections.
• Add utumishi/css/styles.css containing CSS variables and full responsive styling for the header, hero, cards, archive panel, and footer.
• Add utumishi/README.md with recommended repository/folder locations, commands to create files, and instructions to serve the site locally using python3 -m http.server.

Testing

• No automated tests were added or executed for this static site scaffold.

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Codex Task