feat(caddy): expose miccheck-qa admin/api on local domains

Joins caddy to miccheck-qa-net so it can reverse-proxy to the
admin/api containers by name. Uses self-signed internal TLS since
miccheck-qa.com is a local-only hosts-file domain, not a real zone.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

caddy/compose.yml

@@ -34,8 +34,12 @@ services:
           cpus: '0.5'
     networks:
       - proxy
+      - miccheck-qa-net
 
 networks:
   proxy:
     name: proxy
     external: true
+  miccheck-qa-net:
+    name: miccheck-qa-net
+    external: true