ComfyUI serializes every node widget value (even from bypassed nodes)
into the 'prompt' and 'workflow' metadata chunks of generated images
and exported workflows. The api_key widget therefore leaked any real
key to whoever received those files (reported in #8).
BREAKING CHANGE: the OAIAPI_Client node no longer exposes an api_key
widget input. Set the OPENAI_API_KEY environment variable instead.
If unset, the client falls back to the '-' placeholder, which keeps
keyless inference servers (vLLM, etc) working unchanged.
Closes#8
hekmon