i15-1: Queue page improvements

The queue page should have a number of improvements:

- [ ] A "Clear All" button, with a confirmation pop-up
- [ ] The "Clear History" button should have a confirmation pop-up
- [x] Failed tasks should be visible for a period of time (or until dismissed) in the normal queue view, not just under "historical tasks"

Start by locating the queue page implementation and its existing “Clear History” button. Add confirmation pop-ups for clearing all items and clearing history, then verify that both actions require confirmation and that the queue page still displays its current task states.

Written by the indexing model from the issue text.