Read mails momentarily revert to unread

Describe the bug
When reading mails in an IMAP account with PUSH active, messages that have been read will snap back to the unread state for a few seconds before the action fully syncs to the server, after which the message will correctly return to the read state. This wreaks havoc when the sorting mode is set to "unread first", as pressing the "next" button will often switch to an older message in the thread.

To Reproduce
Steps to reproduce the behavior:

1. Open an IMAP folder with PUSH active
2. Open a thread full of unread messages
3. Move through them rapidly with the next button
4. Observe older messages popping in to the sequence
5. Press back to see the thread list, watch read messages switch into unread state, then switch back to read state

Expected behavior
K-9 should locally remember the read status of messages and sync them back to the server in the background.

Environment (please complete the following information):

• K-9 Mail version: 5.802 (F-Droid)
• Android version: 11 (LineageOS 18.1)
• Device: OnePlus 3T
• Account type: IMAP (Dovecot backend server)

Let me know if you think logs would be helpful for this issue.

No files, tests, or entry points are named. Start by reproducing the issue with an IMAP folder using PUSH active, then inspect the read-state synchronization flow. Done means read messages remain locally marked as read while rapid navigation and the thread list update, with changes syncing to the server in the background.