feat(pages): add GitHub Pages landing page

One-page marketing site for ProtoMQ. Covers the value proposition,
feature highlights, a side-by-side comparison with plain MQTT + custom
binary, live code snippets (schema + CLI), and the benchmark table.

Built as a self-contained index.html with no runtime dependencies —
just fonts from Google Fonts. Designed for the gh-pages branch.

Signed-off-by: Gokhankocmarli <gokhan.kocmarli@gmail.com>

Author: electricalgorithm