That is a valid point. Currently, the backend keeps them in RAM mainly to support multi-device syncing (like the QR handoff feature) during an active session. If a user scans the QR code to open the same inbox on mobile, the backend needs to serve those existing messages to the new client.

However, I'm exploring a 'Transfer & Purge' logic where, once a message is successfully delivered and acknowledged by the primary client, it could be encrypted or removed from the server-side RAM entirely, leaving the responsibility of persistence to the client-side IndexedDB. It’s a delicate balance between UX and the absolute 'zero-trace' goal.