Lab patch: tolerate missing X-Forwarded-For

Upstream emulator/server/persistence_decorator_web.py requires HTTP_X_FORWARDED_FOR (HAProxy). Direct lab access to :8080 falls back to REMOTE_ADDR.

-            client_ip = environment["HTTP_X_FORWARDED_FOR"]
+            client_ip = environment.get("HTTP_X_FORWARDED_FOR") or environment.get(
+                "REMOTE_ADDR", "0.0.0.0"
+            )