feat(web): show last agent text outside collapsed group during active turn

Intermediate narration was hidden inside the collapsed tool group
while the agent was still working. The last AgentText/AgentThought
now stays visible as current status, absorbed only when the turn ends
or newer text replaces it.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

web/src/structured.test.ts

@@ -446,6 +446,40 @@ describe("structured connection: data flow", () => {
     conn.dispose();
   });
 
+  it("keeps last intermediate text outside group while turn is active", () => {
+    const ws = new FakeSocket();
+    const conn = mount({ sockets: [ws] });
+    ws.open();
+    const respondingState: ReducedState = {
+      turn: { responding: true, thinking: false, active_tool_calls: [] },
+    };
+    ws.emit({
+      type: "transcript_snapshot",
+      snapshot: {
+        cursor: 6,
+        rows: [
+          row("user:1", "user", { content: { type: "text", text: "do it" } }),
+          toolRow("tool:1", "one"),
+          row("agent:1", "agent_text", { content: { type: "text", text: "Now fixing" } }),
+          toolRow("tool:2", "two"),
+          row("agent:2", "agent_text", { content: { type: "text", text: "Found more" } }),
+          toolRow("tool:3", "three"),
+        ],
+      },
+    });
+    ws.emit({ type: "reduced_state", state: respondingState });
+    // While the turn is active, the last intermediate text (agent:2) stays
+    // outside the collapsed group so it's visible as current narration.
+    expect(conn.el.querySelector('[data-row-id="agent:2"]')?.closest(".st-tool-group")).toBeNull();
+    // Earlier intermediate text (agent:1) is still inside the group.
+    expect(conn.el.querySelector('[data-row-id="agent:1"]')?.closest(".st-tool-group")).not.toBeNull();
+    // When the turn ends, all intermediate text is absorbed.
+    ws.emit({ type: "reduced_state", state: idleState });
+    expect(conn.el.querySelector('[data-row-id="agent:2"]')?.closest(".st-tool-group")).not.toBeNull();
+    expect(conn.el.querySelector('[data-row-id="agent:1"]')?.closest(".st-tool-group")).not.toBeNull();
+    conn.dispose();
+  });
+
   it("keeps an expanded running tool open without emitting a click when patched", () => {
     const ws = new FakeSocket();
     const conn = mount({ sockets: [ws] });