test: tighten qqbot group config assertion

extensions/qqbot/src/engine/config/group.test.ts

@@ -16,14 +16,14 @@ describe("engine/config/group", () => {
   describe("resolveGroupConfig precedence", () => {
     it("returns defaults when no config exists", () => {
       const cfg = resolveGroupConfig({}, "G1");
-      expect(cfg).toMatchObject({
+      expect(cfg).toStrictEqual({
         requireMention: true,
         ignoreOtherMentions: false,
         toolPolicy: "restricted",
         name: "",
+        prompt: undefined,
         historyLimit: DEFAULT_GROUP_HISTORY_LIMIT,
       });
-      expect(cfg.prompt).toBeUndefined();
     });
 
     it("falls back to wildcard when specific is missing", () => {