Feat: support switch dev/pro server mode.

Author: hzy@singhand.com

docker/.env

@@ -191,7 +191,7 @@ ENABLE_GUNICORN=0
 # GUNICORN_MODE chooses the Gunicorn worker class.
 #   gevent - asynchronous workers based on greenlets (default)
 #   sync   - standard synchronous workers; no gevent monkey patching
-GUNICORN_MODE=sync
+GUNICORN_MODE=gevent
 
 # Number of Gunicorn worker processes
 GUNICORN_WORKERS=4