fix: use :80 instead of domain in Caddyfile (nginx handles TLS)

Nginx home-service-proxy terminates TLS and forwards plain HTTP to
Caddy on port 8080. Caddy doesn't need to match the domain name.

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

Caddyfile

@@ -1,4 +1,4 @@
-pkm.hyungi.net {
+:80 {
     encode gzip
 
     # API + 문서 → FastAPI