Provide QR Code for E2E Encryption Key transfer between devices (like Signal)

Description:

It's really a weak user experience, when end-users who doesn't have so much experience with E2E have to save the E2E Encryption String and save it and re-type it every time they install the app on a new device.

Signal (and other known apps) is doing this much better and provide a QR-Code or have a list of trusted devices with which you can transfer your E2E Encryption Key to the Desktop App for example and doesn't have to type anything or remember it. You can still backup the code, but the workflow for now lacks UX in Rocket Chat.

Expected feature:

Actual behavior:

Server Setup Information:

• Version of Rocket.Chat Server: 7.5.1
• License Type: Starter
• Number of Users: 40
• Operating System: Linux
• Deployment Method: docker
• Number of Running Instances: 1
• DB Replicaset Oplog: mongodb://rocketchat-db:27017/local?replicaSet=rs0
• NodeJS Version: 22.13.1
• MongoDB Version: 7.0.5

Client Setup Information

• Desktop App: 4.1.0
• Operating System: Windows / macOS

No file, test, or entry point is named. Start by reviewing the existing E2E encryption-key setup and transfer flow in the desktop app, using the expected and actual behavior screenshots as context. Define a secure QR-code or trusted-device workflow for Windows and macOS, then verify that a transferred key restores encrypted access without requiring manual re-entry.