LAN proxy: no 1 MB upload cap

docker/nginx-api-proxy.conf

@@ -24,6 +24,10 @@ location /api {
     proxy_set_header Connection $http_connection;
     # A live socket outlives the 60s default by design.
     proxy_read_timeout 1d;
+    # nginx's 1 MB default would 413 any larger artifact upload; the backend
+    # enforces MAX_ARTIFACT_BYTES itself, so the body streams through as is.
+    client_max_body_size 0;
+    proxy_request_buffering off;
 }
 
 # Unchanged from the stub: the API docs stay off the frontend's origin.