Fix stale default-open doc comments per argus's review

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).

hive-agent/src/stream_enrich.rs

@@ -268,9 +268,11 @@ fn classify_assistant_content(content: &[Value], ctx: &mut ClassifyCtx) -> Vec<T
 }
 
 /// `_category === 'rich'` tools used to get an expandable row (diff body
-/// for Edit, default-open markdown for send, plain for everything else with
-/// a body). That's now just "does this row have a body" — `body.is_some()`
-/// on the returned [`TermMsg`] *is* the expandable signal, no separate flag.
+/// for Edit, markdown body for send, plain for everything else with a
+/// body). That's now just "does this row have a body" — `body.is_some()`
+/// on the returned [`TermMsg`] *is* the expandable signal, no separate
+/// flag; whether it renders open or collapsed is a uniform client-side
+/// preference, not something this function decides.
 fn classify_tool_use(c: &Value) -> TermMsg {
     let name = c.get("name").and_then(Value::as_str).unwrap_or("");
     let input = c.get("input").cloned().unwrap_or_else(|| json!({}));
@@ -418,12 +420,16 @@ fn classify_task_event(v: &Value) -> Option<TermMsg> {
 
 /// Pre-compute the expandable body for rich tool entries.
 ///
-/// Returns `Some((body, body_type))` where `body_type` tells the frontend
-/// which renderer to use:
-/// - `"diff"` → `api.detailsDiff` (colour-coded `+`/`-` lines)
-/// - `"plain"` → `api.details` (plain `<pre>` block)
-/// - `"markdown"` → `api.detailsOpenMd` (markdown rendered via marked + `DOMPurify`,
-///   default-open; used for message-bearing tools: `send`)
+/// Returns `Some((body, body_type))` where `body_type` becomes the
+/// `TermMsg`'s `body_format` and tells the frontend which renderer to use:
+/// - `"diff"` → colour-coded `+`/`-` lines
+/// - `"plain"` (`None` on the wire) → a plain `<pre>` block
+/// - `"markdown"` → rendered via `marked` + `DOMPurify`; used for
+///   message-bearing tools: `send`
+///
+/// Whether the resulting row renders open or collapsed is a uniform
+/// client-side preference (the operator's expand-tool-output setting),
+/// not something this function or its `body_type` decides.
 ///
 /// Returns `None` for tools that have no body at all.
 ///

hive-agent/src/term_msg.rs

@@ -101,14 +101,13 @@ impl TermMsg {
 /// Per-connection/per-request classification state. A live SSE stream keeps
 /// one of these alive for the connection's lifetime — `tool_use` id → name
 /// correlation, so a `tool_result` can tell it's answering a `recv` call and
-/// render as a default-open markdown message body. The history endpoint
+/// render its body as markdown instead of plain text. The history endpoint
 /// uses a fresh one per page: correlation only works within the page
 /// actually returned, not across the live/history boundary. Accepted
-/// degradation (same shape as the turn-timestamp fallback documented in
-/// `docs/terminal-rendering.md`) — the only user-visible effect is a `recv`
-/// result whose `tool_use` fell on the other side of a page/reconnect
-/// boundary rendering as a plain block instead of default-open markdown,
-/// not a functional loss.
+/// degradation — the only user-visible effect is a `recv` result whose
+/// `tool_use` fell on the other side of a page/reconnect boundary rendering
+/// its body as plain text instead of markdown (open/collapsed state is a
+/// uniform client-side preference either way, not affected by this).
 #[derive(Default)]
 pub struct ClassifyCtx {
     tool_name_by_id: HashMap<String, String>,

hive-agent/src/web_ui/stream.rs

@@ -79,9 +79,10 @@ pub(super) async fn events_history(
     // replay and live tail deliver identical shapes. The DB stores raw
     // events; classification is applied at read time here (see
     // `crate::term_msg`). One `ClassifyCtx` for the whole page — tool_use→
-    // name correlation (for default-open `recv` results) only works within
-    // a single page/connection, not across the live/history boundary; see
-    // that module's doc for why that's an accepted degradation.
+    // name correlation (for markdown-vs-plain `recv` result bodies) only
+    // works within a single page/connection, not across the live/history
+    // boundary; see that module's doc for why that's an accepted
+    // degradation.
     let mut ctx = ClassifyCtx::default();
     let events: Vec<TermEnvelope> = events
         .into_iter()