Fix hidden-message leakage into plugin prompts

tests/recall-hide-bypass.mjs

@@ -0,0 +1,33 @@
+import assert from "node:assert/strict";
+
+import { buildRecallRecentMessagesController } from "../retrieval/recall-controller.js";
+
+const chat = [
+  { is_user: false, is_system: true, mes: "greeting/system" },
+  {
+    is_user: false,
+    is_system: true,
+    mes: "managed hidden assistant",
+    extra: { __st_bme_hide_managed: true },
+  },
+  { is_user: true, is_system: false, mes: "user message" },
+  { is_user: false, is_system: true, mes: "real system" },
+  { is_user: false, is_system: false, mes: "visible assistant" },
+];
+
+const recentMessages = buildRecallRecentMessagesController(chat, 6, "", {
+  formatRecallContextLine(message) {
+    return `[${message.is_user ? "user" : "assistant"}]: ${message.mes}`;
+  },
+  normalizeRecallInputText(value = "") {
+    return String(value || "").trim();
+  },
+});
+
+assert.deepEqual(recentMessages, [
+  "[assistant]: managed hidden assistant",
+  "[user]: user message",
+  "[assistant]: visible assistant",
+]);
+
+console.log("recall-hide-bypass tests passed");