refactor: centralize history context wrapping

src/auto-reply/reply/history.test.ts

@@ -3,6 +3,7 @@ import {
   appendHistoryEntry,
   buildHistoryContext,
   buildHistoryContextFromEntries,
+  buildHistoryContextFromMap,
   HISTORY_CONTEXT_MARKER,
 } from "./history.js";
 import { CURRENT_MESSAGE_MARKER } from "./mentions.js";
@@ -60,4 +61,31 @@ describe("history helpers", () => {
       "three",
     ]);
   });
+
+  it("builds context from map and appends entry", () => {
+    const historyMap = new Map<string, { sender: string; body: string }[]>();
+    historyMap.set("room", [
+      { sender: "A", body: "one" },
+      { sender: "B", body: "two" },
+    ]);
+
+    const result = buildHistoryContextFromMap({
+      historyMap,
+      historyKey: "room",
+      limit: 3,
+      entry: { sender: "C", body: "three" },
+      currentMessage: "current",
+      formatEntry: (entry) => `${entry.sender}: ${entry.body}`,
+    });
+
+    expect(historyMap.get("room")?.map((entry) => entry.body)).toEqual([
+      "one",
+      "two",
+      "three",
+    ]);
+    expect(result).toContain(HISTORY_CONTEXT_MARKER);
+    expect(result).toContain("A: one");
+    expect(result).toContain("B: two");
+    expect(result).not.toContain("C: three");
+  });
 });