The dashboard settings button toggles

It only ever opened, so the way out of the settings panel was somewhere else.
Pressing it again closes it, and it carries the pressed state the other dock
toggles do.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

frontend/src/components/Dashboard/DashboardEditor.tsx

@@ -638,11 +638,19 @@ export function DashboardEditor({
                   <Button
                     variant="ghost"
                     size="icon"
-                    className="size-11 text-muted-foreground md:size-8"
+                    className={cn(
+                      "size-11 text-muted-foreground md:size-8",
+                      settingsOpen && "text-primary",
+                    )}
                     onClick={() => {
+                      if (settingsOpen) {
+                        setSettingsOpen(false)
+                        return
+                      }
                       setSelected(null)
                       setSettingsOpen(true)
                     }}
+                    aria-pressed={settingsOpen}
                     aria-label="Dashboard settings"
                     data-testid="edit-dashboard"
                   >