Point links at git.coffeylabs.org after the move from GitHub

GitHub took the organisation's repos and GHCR offline on 2026-09-20. Repo,
release, raw-file and clone links now go to Gitea at git.coffeylabs.org,
container images to registry.coffeylabs.org, and GitLab-style /-/blob paths
to Gitea's /src/branch form. Go module paths are identifiers and stay as
they are; links to GitHub issues and pull requests are left as history.

src/components/Landing.tsx

@@ -117,7 +117,7 @@ export function Landing({
           */}
           <a href="https://games.jcoffey.dev/">The rest of the games</a>
           {' · '}
-          <a href="https://github.com/jcoffey-dev/world-conquest">Source</a>
+          <a href="https://git.coffeylabs.org/jcoffey-dev/world-conquest">Source</a>
         </p>
         <p>
           World Conquest is free software under the{' '}