dsh-panel-fold: Move all-panel icons in sidebar into "More"

After installing several plugins in DSH, the global panel entry area at the top of the left sidebar consumes 36px per panel; seven or eight rows of this will squeeze the workspace and session list into a narrow strip. meihuaanying/dsh-panel-fold (MIT, 0.1.0) does not modify `ui-sidebar`. Instead, it uses a `MutationObserver` to detect changes in the panel list `nav` and a single CSS rule to collapse that row into the bottom of the existing "More" button, while also providing a toggle switch and `localStorage` persistence.