feat: add Race Replay project page and blog post

[tomarra]

Summary

This PR adds Race Replay, a new web application for analyzing physical passes in endurance races, to the Cloudgate Studios portfolio. Includes a dedicated project detail page, blog announcement post, and project metadata.

Changes

• New project detail page (src/projects/racereplay/index.njk): Full-featured project showcase with hero section, app icon, tagline, and description of Race Replay's core functionality
• Launch blog post (src/blog/2026-06-17-racereplay.md): Announcement post explaining the problem Race Replay solves (chip time results don't show physical passes), how it works, and implementation notes
• Project registry update (src/_data/projects.json): Added Race Replay metadata with slug, description, icon, platform (web), and marked as active and featured

Notable Details

• Race Replay is positioned as a web app with no installation required
• The project emphasizes solving a specific problem: determining who actually passed whom on course based on per-athlete start times and checkpoint splits, rather than adjusted chip times
• Blog post mentions the project was built using Claude Code, similar to the recent Bike Share Buddy rewrite
• Both the project page and blog post link to the live application at racereplay.app

https://claude.ai/code/session_01S89roJcg7JC6o5NXbvk6fJ

[github-actions]

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