refactor(infra) : align prod setup with Lesstime pattern

Single container with supervisord (Nginx + PHP-FPM), 3-stage
Dockerfile build, pre-built image from registry, port 8086.

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

infra/prod/supervisord.conf

@@ -0,0 +1,28 @@
+[supervisord]
+nodaemon=true
+user=root
+logfile=/dev/null
+logfile_maxbytes=0
+pidfile=/var/run/supervisord.pid
+
+[program:php-fpm]
+command=php-fpm -F
+autostart=true
+autorestart=true
+stdout_logfile=/dev/stdout
+stdout_logfile_maxbytes=0
+stderr_logfile=/dev/stderr
+stderr_logfile_maxbytes=0
+stopasgroup=true
+stopsignal=QUIT
+
+[program:nginx]
+command=nginx -g "daemon off;"
+autostart=true
+autorestart=true
+stdout_logfile=/dev/stdout
+stdout_logfile_maxbytes=0
+stderr_logfile=/dev/stderr
+stderr_logfile_maxbytes=0
+stopasgroup=true
+stopsignal=QUIT