Show a reply's steps, and catch up on a reply whose live push was missed

A reply that works through tools now shows its latest tool step under
"is thinking…" (not its closing note, which is the answer). While a reply
is due, the open conversation checks the session's latest messages every
few seconds (api/admin/bots/session-messages) and replays any it missed
as server:bot-message, so the thread, rail and unread all take it and the
thinking row can't stay up until a reload. MCP and custom tool steps read
in words ("Using Exa search (web search exa)").

Co-Authored-By: Claude Opus 5.5 <[email protected]>

src/bots-queue/describe-job-step.test.ts

@@ -48,10 +48,21 @@ describe("describeJobStep", () => {
                 tool_calls: [
                     { id: "a", name: "browser_navigate", arguments: "{}" },
                     { id: "b", name: "browser_click", arguments: "{}" },
-                    { id: "c", name: "some_mcp_tool", arguments: "{}" },
+                    { id: "c", name: "get_weather", arguments: "{}" },
                 ],
             })?.text,
-        ).toBe("Using the browser, Using some_mcp_tool");
+        ).toBe("Using the browser, Using get weather");
+    });
+
+    test("names an MCP server's tool in words", () => {
+        expect(
+            describeJobStep({
+                index: 0,
+                text: null,
+                candidate,
+                tool_calls: [{ id: "a", name: "exa_search__web_search_exa", arguments: "{}" }],
+            })?.text,
+        ).toBe("Using Exa search (web search exa)");
     });
 
     test("keeps the first line of a text-only turn, cut to one line", () => {