Multiple UI components displayed executionSummary.totalTokens (cumulative
sum of total_tokens across all API rounds) as the subagent token count.
For a subagent making 87 requests with ~51K prompt each, this inflated
to 4.4M — misleading users into thinking it was context window usage.
Switch all subagent token displays to use outputTokens (what the model
actually generated), aligning with the loading indicator which already
correctly shows output tokens only.
Closes#5683