revert: remove Chromium/Playwright deps from Dockerfile; add supervisorctl support

- Revert Dockerfile to before the Playwright system deps / Chromium copy
  (commit 6e9726f). The ConnectError is a service-not-running issue, not
  a missing-browser issue.

- Add [unix_http_server], [supervisorctl], and [rpcinterface:supervisor]
  sections so 'supervisorctl status' works inside the container.

- Redirect scanner stdout/stderr to /var/log/scanner.log so startup
  errors are inspectable.

supervisord.conf

@@ -4,6 +4,16 @@ logfile=/var/log/supervisor/supervisord.log
 pidfile=/var/run/supervisord.pid
 user=root
 
+[unix_http_server]
+file=/var/run/supervisor.sock
+chmod=0700
+
+[supervisorctl]
+serverurl=unix:///var/run/supervisor.sock
+
+[rpcinterface:supervisor]
+supervisor.rpcinterface_factory = supervisor.rpcinterface:make_main_rpcinterface
+
 [program:nginx]
 command=nginx -g "daemon off;" -c /etc/nginx/conf.d/default.conf
 autostart=true
@@ -61,9 +71,9 @@ directory=/app
 autostart=true
 autorestart=true
 startsecs=10
-stdout_logfile=/dev/stdout
+stdout_logfile=/var/log/scanner.log
 stdout_logfile_maxbytes=0
-stderr_logfile=/dev/stderr
+stderr_logfile=/var/log/scanner.log
 stderr_logfile_maxbytes=0
 stopwaitsecs=10
 killasgroup=true