server: Router wasn't propagating the client disconnects fully to the child, the response wait could cause a delayed cancellation (#29707)

* Router wasn't propagating the client disconnects fully to the child, the response wait could cause a delayed cancellation

* tests: satisfy router disconnect type check

* server : remove timing-sensitive router cancellation test

Assisted-by: Codex

tools/server/server-models.cpp

@@ -2836,9 +2836,10 @@ server_http_proxy::server_http_proxy(
     cli->set_write_timeout(timeout_read, 0); // reversed for cli (client) vs srv (server)
     cli->set_read_timeout(timeout_write, 0);
     this->status = 500; // to be overwritten upon response
-    this->cleanup_pipes = [pipe]() {
+    this->cleanup_pipes = [pipe, cli]() {
         pipe->close_read();
         pipe->close_write();
+        cli->stop();
     };
 
     // wire up the receive end of the pipe