Broken relative links on `/contributing` page

[mst-mkt]

Summary

Relative links on the /contributing page point to trynova.dev instead of the GitHub repo.

e.g. ARCHITECTURE.md → https://trynova.dev/ARCHITECTURE.md (404)

Cause

The page fetches CONTRIBUTING.md from the Nova repo and renders it without resolving relative paths against the GitHub base URL.

Suggested fix

Use something like marked-base-url to rewrite relative links to point to the repo.