Add sort options to the sidebar collection view

[awulz]

Is your feature request related to a problem? Please describe.
Currently there is no way to sort requests and folders in the sidebar. When a collection grows larger, it becomes hard to find specific requests without manual reordering.

Describe the solution you'd like
Add a single sort button in the sidebar header that cycles through sort modes on each click. The sort is view-only and does not change the saved order in the backend.

The button cycles through the following states:

Default — Only the sort icon is visible. The last manually saved order is restored.
A→Z — The list is sorted alphabetically ascending. Applied recursively to all folders and their contents.
Z→A — The list is sorted alphabetically descending. Applied recursively.
Last modified ↑ — Sorted by last modified date, newest entries first. Applied recursively.
Last modified ↓ — Sorted by last modified date, oldest entries first. Applied recursively.
Clicking the button again after the last state resets back to the default manual order.

Each icon displays a tooltip on hover to explain its current action, so users can understand the sorting behaviour without prior knowledge.

Describe alternatives you've considered

Additional context

Design:

2026-03-05.14-36-17.mp4