New version notification

[kchudy]

Description

As a user, I want to be notified when a new application version is available.

AC:

• Display a persistent toast notification at the bottom of the screen: "New version is available" with an "Update now" action and a dismiss (×) button
• The sidebar update icon changes to indicate an available update (animated)
• Clicking "Update now" initiates the update process

[frq-asgard-migo]

As an administrator, I would like to test new application versions before users are notified about available updates.
Is there a way to temporarily suppress the update notification and re-enable it once the update has been verified?
Currently, this has to be configured manually on each client.