Sidebar (N-panel) tab labels: add option for vertical text direction

Currently N-panel tab labels are hard-coded as horizontal text rotated 90° clockwise. Please add a user option to display them as vertical top-to-bottom text instead. This should be a simple preference toggle (e.g. in Interface > Sidebar), so each user can choose what works best for their workflow and visual comfort. No specific language or region requirement — just a basic UI customization option.