fix: harden queue retry debounce and add regression tests

src/gateway/agent-prompt.test.ts

@@ -1,5 +1,6 @@
 import { describe, expect, it } from "vitest";
 import { buildHistoryContextFromEntries } from "../auto-reply/reply/history.js";
+import { extractTextFromChatContent } from "../shared/chat-content.js";
 import { buildAgentMessageFromConversationEntries } from "./agent-prompt.js";
 
 describe("gateway agent prompt", () => {
@@ -15,6 +16,24 @@ describe("gateway agent prompt", () => {
     ).toBe("hi");
   });
 
+  it("extracts text from content-array body when there is no history", () => {
+    expect(
+      buildAgentMessageFromConversationEntries([
+        {
+          role: "user",
+          entry: {
+            sender: "User",
+            body: [
+              { type: "text", text: "hi" },
+              { type: "image", data: "base64-image", mimeType: "image/png" },
+              { type: "text", text: "there" },
+            ] as unknown as string,
+          },
+        },
+      ]),
+    ).toBe("hi there");
+  });
+
   it("uses history context when there is history", () => {
     const entries = [
       { role: "assistant", entry: { sender: "Assistant", body: "prev" } },
@@ -45,4 +64,34 @@ describe("gateway agent prompt", () => {
 
     expect(buildAgentMessageFromConversationEntries([...entries])).toBe(expected);
   });
+
+  it("normalizes content-array bodies in history and current message", () => {
+    const entries = [
+      {
+        role: "assistant",
+        entry: {
+          sender: "Assistant",
+          body: [{ type: "text", text: "prev" }] as unknown as string,
+        },
+      },
+      {
+        role: "user",
+        entry: {
+          sender: "User",
+          body: [
+            { type: "text", text: "next" },
+            { type: "text", text: "step" },
+          ] as unknown as string,
+        },
+      },
+    ] as const;
+
+    const expected = buildHistoryContextFromEntries({
+      entries: entries.map((e) => e.entry),
+      currentMessage: "User: next step",
+      formatEntry: (e) => `${e.sender}: ${extractTextFromChatContent(e.body) ?? ""}`,
+    });
+
+    expect(buildAgentMessageFromConversationEntries([...entries])).toBe(expected);
+  });
 });