cdf233378c
The API container and tool instances share the 'backend' Docker network
(connect_container_to_network at tool_instances.py:1576). cloudflared
runs INSIDE the api container, so localhost:host_port is unreachable.
The original container_name:internal_port is correct for networking.
The 'app error 0' is an application-level issue, not networking.
This reverts commit a8fbca9.