Requesting mnemonic from time to time

I've found that each time the desktop client update or the upgrade of the server I have to enter the mnemonic, as the E2E becomes disabled. Consequently, the desktop client re-syncs all the encrypted files. In my opinion, this is resource consuming and excessive operation.

UPD Moreover, it happens from time to time event without upgrading!

Is that possible to ommit it?

Start by reproducing the mnemonic prompt after a desktop-client update, server upgrade, and without either, then trace the desktop client's E2E state and encrypted-file resync flow. Done means the client preserves E2E access when appropriate, avoids unnecessary full resynchronization, and still prompts when the mnemonic is genuinely required.

Written by the indexing model from the issue text.