Task: Send a private message on Zulip

n8n workflow JSON:
{"id":"126","name":"Send a private message on Zulip","nodes":[{"name":"On clicking 'execute'","type":"n8n-nodes-base.manualTrigger","position":[250,300],"parameters":{},"typeVersion":1},{"name":"Zulip","type":"n8n-nodes-base.zulip","position":[450,300],"parameters":{"to":[]},"credentials":{"zulipApi":""},"typeVersion":1}],"active":false,"settings":{},"connections":{"On clicking 'execute'":{"main":[[{"node":"Zulip","type":"main","index":0}]]}}}