Add TrafficAnalytics import to main domain block (#148)

Analytics requests go to the main domain (separationofconcerns.dev), not
the admin domain. The TrafficAnalytics snippet must be imported in the
main domain block to proxy /.ghost/analytics/* to traffic-analytics.

Author: noahwhite

opentofu/modules/vultr/instance/userdata/ghost-compose/caddy/Caddyfile

@@ -8,6 +8,9 @@
 
     tls /certs/cloudflare-origin.crt /certs/cloudflare-origin.key
 
+    # Traffic Analytics service (proxies /.ghost/analytics/* to traffic-analytics container)
+    import snippets/TrafficAnalytics
+
     # Health check authentication via token header
     # Token is sourced from .env.secrets via Docker Compose env_file
     @health_check {