Dynamic tray icon for updates

[ComputelessComputer]

Update indicator in tray icon

Users don't know an update is available until they open the app. Show a visual indicator on the tray icon (like Ollama does) so users can see at a glance that a new version is ready.

[yujonglee]

Something like this: #3199

[ComputelessComputer]

do after char rebrand

[elstua]

made it there #4251