feat(ui): let users hide context rail surfaces

A trailing configure button on the rail — outside the sortable list and the
digit shortcuts — opens a dialog that toggles each surface. The choice is
stored as the hidden set so newly added surfaces appear for everyone, and
the rail and the mod+alt+digit switcher share the same visibility filter, so
badges and shortcuts always agree. Hidden surfaces keep their data and stay
reachable from the command palette.

packages/ui/src/hooks/useKeyboardShortcuts.ts

@@ -499,6 +499,7 @@ export const useKeyboardShortcuts = () => {
           const panel = state.contextPanelByDirectory[directory];
           const visibleSurfaces = getVisibleContextRailSurfaces({
             railOrder: state.contextRailOrder,
+            hiddenSurfaces: state.contextRailHiddenSurfaces,
             planModeEnabled: useFeatureFlagsStore.getState().planModeEnabled,
             isVSCode: isVSCodeRuntime(),
             screenWidth: window.innerWidth,