fix(ui): return Escape focus to the rail item and read rail direction from the panel

A desktop side panel hides once collapsed, so Escape hands focus to its visible rail item instead of the hidden disclosure. Rail selection reads the panel's collapsed class rather than the store, which follows it a microtask late.

src/ui/panelChrome.js

@@ -163,6 +163,22 @@ export class PanelChrome {
         this._locationSearch.value = '';
         this._locationSearch.blur();
       },
+      // A desktop side panel hides entirely once collapsed; its rail item
+      // takes the focus its own disclosure can no longer hold.
+      returnFocusTo: () => {
+        const panel = document.getElementById(panelId);
+        if (!panel?.getClientRects || panel.getClientRects().length > 0)
+          return null;
+        const item = document.querySelector?.(
+          `.ui-rail [data-rail-item="${panelId}"]`,
+        );
+        return item &&
+          !item.disabled &&
+          item.getClientRects().length > 0 &&
+          getComputedStyle(item).visibility === 'visible'
+          ? item
+          : null;
+      },
     });
   }