Reduce staging to 2 gunicorn workers (saves ~700 MB RAM)

Staging only needs minimal workers for pre-deploy testing.
Production keeps 4 workers.

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

Author: vthorsteinsson

config/gunicorn_config.py

@@ -8,7 +8,7 @@
 
 bind = "unix:" + DIR + "gunicorn.sock"
 worker_class = "gevent"
-workers = 4
+workers = 2 if "staging" in proc_name else 4
 timeout = 120
 # Note: preload_app is not compatible with PyPy + async workers (gevent/eventlet)
 max_requests = 1000