Keep HeyCatch short links on the public host.

A relative redirect from the static vhost was rewritten with the container port, so links like /y landed on hesychia.ai:8082.

roles/web-static/templates/nginx.conf.j2

@@ -58,6 +58,17 @@ server {
 {%- endif %}
 {%- endif %}
 
+{% if a.name == 'chat_web_app' and a.env == 'prod' %}
+    # HeyCatch short links.
+    # f Facebook, h Threads, i Instagram, l LinkedIn, r Reddit, x X, y YouTube.
+    # Relative Location: this vhost listens on the container port. An absolute
+    # redirect would publish that port (hesychia.ai:8082).
+    location ~ ^/([a-z0-9])/?$ {
+        absolute_redirect off;
+        return 302 /?utm_source=heycatch&utm_campaign=$1;
+    }
+{% endif %}
+
 {% if app_catalog[a.name].error_page_404 | default('') %}
     error_page 404 {{ app_catalog[a.name].error_page_404 }};