Two issues caused duplicate messages to be sent to users:
1. System messages (from subagent): processSystemMessage set SendResponse:true,
causing runAgentLoop to publish outbound. Then Run() also published outbound
using the returned response string, resulting in two identical messages.
Fix: processSystemMessage now returns empty string since runAgentLoop already
handles the send.
2. Message tool double-send: When LLM called the "message" tool during
processing, it published outbound immediately. Then Run() published the
final response again. Fix: Track whether MessageTool sent a message in the
current round (sentInRound flag, reset on each SetContext call). Run()
checks HasSentInRound() before publishing to avoid duplicates.
132fe7db51