fix: 解散群作废 scheduled 时消息级回执改用 rejected

internal/app/group/group_test.go

@@ -296,6 +296,16 @@ WHERE m.id='gm1' AND d.endpoint_id='bob'`).Scan(&reason)
 	if err != nil || state != "completed" || mreason != "group_dissolved" {
 		t.Fatalf("state=%s reason=%s err=%v", state, mreason, err)
 	}
+	// 消息级回执 state 须为协议枚举 rejected，不得写成消息状态 completed（issue #6 / DEVELOPMENT 6.4）
+	var rState, rReason, rEndpoint string
+	err = db.Read.QueryRow(`
+SELECT state, reason, endpoint_id FROM receipts WHERE sender_id='alice' AND msg_id='gm2'`).Scan(&rState, &rReason, &rEndpoint)
+	if err != nil {
+		t.Fatalf("receipt for dissolved scheduled: %v", err)
+	}
+	if rState != "rejected" || rReason != "group_dissolved" || rEndpoint != "" {
+		t.Fatalf("receipt state=%q reason=%q endpoint=%q want rejected/group_dissolved/empty", rState, rReason, rEndpoint)
+	}
 	// 同编号新建群
 	created2, err := gApp.Create(ctx, "alice", &protocol.GroupCreate{
 		V: protocol.Version, Type: protocol.TypeGroupCreate, RID: "6",

internal/app/group/void.go

@@ -139,10 +139,11 @@ UPDATE messages SET state = 'completed', reason = ? WHERE seq = ? AND state = 's
 			return execErr
 		}
 		if r.receipt != 0 {
+			// 消息级作废回执：endpoint_id 空，state=rejected（DEVELOPMENT 6.4）；消息行仍为 completed
 			if _, execErr := tx.Exec(`
 INSERT INTO receipts(sender_id, msg_id, endpoint_id, state, reason, created_at, acked)
 VALUES(?,?,?,?,?,?,0)`,
-				r.senderID, r.msgID, "", "completed", reasonGroupDissolved, nowMs); execErr != nil {
+				r.senderID, r.msgID, "", "rejected", reasonGroupDissolved, nowMs); execErr != nil {
 				return execErr
 			}
 		}