Add health and metrics routes to Journal route config

The route files existed but weren't registered in the explicit routes.ts,
so React Router never compiled them into the build.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

apps/journal/app/routes.ts

@@ -20,4 +20,6 @@ export default [
   route("activities/:id", "routes/activities.$id.tsx"),
   route("users/:username", "routes/users.$username.tsx"),
   route("privacy", "routes/privacy.tsx"),
+  route("api/health", "routes/api.health.ts"),
+  route("api/metrics", "routes/api.metrics.ts"),
 ] satisfies RouteConfig;