Before this fix, clicking on a task list item with the same name as another one, both would get marked as done. This was due to the mechanism which walks the dom tree to look for the node to update used its content for comparison. To prevent this, this fix first added unique ids to all task list items and then compared the nodes based on their id instead of the content.
Resolves https://kolaente.dev/vikunja/vikunja/issues/2091
Username and password are validated in the api for length and whitespaces. Previously, the api would tell the user "hey you got it wrong" but the error was not reflected properly in the UI. This change implements a client-side validation which mirrors the one from the api, allowing instant validation and better error UX.
