ClassifyCtx's tool_use-id correlation gates markdown-vs-plain body
format for a recv result, not open/collapsed state — that's always
the operator's uniform preference now. 5 backend comments still
described it as controlling "default-open" rendering, contradicting
the actual render path and this PR's own rewritten docs.
Also fixed useAgentState.ts's stale comment promising an
SSE-triggered refresh model "in a later commit" — that's permanently
off the table now that the terminal stream's kind tag is gone by
design (argus flagged this as a drive-by, not blocking, but it's a
one-line cause-and-effect of this same PR so fixing it here).
907567ef76