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/components/layout/ContextPanelRail.tsx

@@ -36,6 +36,7 @@ import { cn } from '@/lib/utils';
 import { useFeatureFlagsStore } from '@/stores/useFeatureFlagsStore';
 import { useGitStatus } from '@/stores/useGitStore';
 import { normalizeContextPanelDirectoryKey, useUIStore } from '@/stores/useUIStore';
+import { ContextRailSurfacesDialog } from './ContextRailSurfacesDialog';
 
 const RAIL_TOOLTIP_DELAY_MS = 150;
 // Hold the surface-switch modifier for this long before revealing the order
@@ -161,6 +162,7 @@ export const ContextPanelRail: React.FC = () => {
   const panelState = useUIStore((state) => (directoryKey ? state.contextPanelByDirectory[directoryKey] : undefined));
   const workStatusPanelVisible = useUIStore((state) => state.workStatusPanelVisible);
   const contextRailOrder = useUIStore((state) => state.contextRailOrder);
+  const contextRailHiddenSurfaces = useUIStore((state) => state.contextRailHiddenSurfaces);
   const setContextRailOrder = useUIStore((state) => state.setContextRailOrder);
   const openContextSurface = useUIStore((state) => state.openContextSurface);
   const shortcutOverrides = useUIStore((state) => state.shortcutOverrides);
@@ -256,12 +258,15 @@ export const ContextPanelRail: React.FC = () => {
   const surfaces = React.useMemo(() => {
     return getVisibleContextRailSurfaces({
       railOrder: contextRailOrder,
+      hiddenSurfaces: contextRailHiddenSurfaces,
       planModeEnabled,
       isVSCode: isVSCodeRuntime(),
       screenWidth,
       tabs,
     });
-  }, [contextRailOrder, planModeEnabled, screenWidth, tabs]);
+  }, [contextRailHiddenSurfaces, contextRailOrder, planModeEnabled, screenWidth, tabs]);
+
+  const [isSurfacesDialogOpen, setIsSurfacesDialogOpen] = React.useState(false);
 
   const handleDragEnd = React.useCallback((event: DragEndEvent) => {
     const { active, over } = event;
@@ -331,6 +336,24 @@ export const ContextPanelRail: React.FC = () => {
           })}
         </SortableContext>
       </DndContext>
+      {/* Outside the sortable list on purpose: this button takes no digit,
+          cannot be dragged, and configures the rail rather than living on it. */}
+      <Tooltip delayDuration={RAIL_TOOLTIP_DELAY_MS}>
+        <TooltipTrigger asChild>
+          <button
+            type="button"
+            aria-label={t('contextRail.configure.open')}
+            onClick={() => setIsSurfacesDialogOpen(true)}
+            className="flex h-9 w-9 items-center justify-center rounded-md text-muted-foreground/70 transition-colors hover:text-foreground"
+          >
+            <Icon name="equalizer-2" className="h-[18px] w-[18px]" />
+          </button>
+        </TooltipTrigger>
+        <TooltipContent side="left" sideOffset={8}>
+          {t('contextRail.configure.open')}
+        </TooltipContent>
+      </Tooltip>
+      <ContextRailSurfacesDialog open={isSurfacesDialogOpen} onOpenChange={setIsSurfacesDialogOpen} />
     </nav>
   );
 };

packages/ui/src/components/layout/ContextRailSurfacesDialog.tsx

@@ -0,0 +1,78 @@
+import React from 'react';
+import { useI18n } from '@/lib/i18n';
+import { useUIStore } from '@/stores/useUIStore';
+import { SettingsCheckboxRow } from '@/components/sections/shared/SettingsSection';
+import { Button } from '@/components/ui/button';
+import {
+  Dialog,
+  DialogContent,
+  DialogDescription,
+  DialogHeader,
+  DialogTitle,
+} from '@/components/ui/dialog';
+import { sortContextSurfaces } from '@/lib/surfaces/registry';
+
+/**
+ * Which surfaces the context rail shows. Everything is on by default and the
+ * choice is stored as the *hidden* set, so a surface added in a later release
+ * appears for everyone rather than staying invisible to whoever had saved
+ * settings before it existed. Hidden surfaces also leave the digit shortcuts
+ * (the rail and the shortcut share one visibility filter).
+ */
+export const ContextRailSurfacesDialog: React.FC<{
+  open: boolean;
+  onOpenChange: (open: boolean) => void;
+}> = ({ open, onOpenChange }) => {
+  const { t } = useI18n();
+  const contextRailOrder = useUIStore((state) => state.contextRailOrder);
+  const hidden = useUIStore((state) => state.contextRailHiddenSurfaces);
+  const setSurfaceVisible = useUIStore((state) => state.setContextRailSurfaceVisible);
+  const setHiddenSurfaces = useUIStore((state) => state.setContextRailHiddenSurfaces);
+
+  // The full registry in the user's rail order — including surfaces a runtime
+  // filter currently drops, so a choice made on desktop is editable anywhere.
+  const surfaces = React.useMemo(() => sortContextSurfaces(contextRailOrder), [contextRailOrder]);
+
+  const allVisible = hidden.length === 0;
+  const noneVisible = surfaces.every((surface) => hidden.includes(surface.id));
+
+  return (
+    <Dialog open={open} onOpenChange={onOpenChange}>
+      <DialogContent className="max-w-md">
+        <DialogHeader>
+          <DialogTitle>{t('contextRail.configure.dialogTitle')}</DialogTitle>
+          <DialogDescription>{t('contextRail.configure.dialogDescription')}</DialogDescription>
+        </DialogHeader>
+
+        <div className="flex flex-col">
+          {surfaces.map((surface) => (
+            <SettingsCheckboxRow
+              key={surface.id}
+              settingsItem={`layout.context-rail.surface.${surface.id}`}
+              checked={!hidden.includes(surface.id)}
+              onChange={(checked) => setSurfaceVisible(surface.id, checked)}
+              label={t(surface.labelKey)}
+              ariaLabel={t(surface.labelKey)}
+            />
+          ))}
+        </div>
+
+        {!allVisible ? (
+          <div className="flex items-center justify-between border-t pt-3">
+            {noneVisible ? (
+              <span className="text-xs text-destructive">{t('contextRail.configure.noneWarning')}</span>
+            ) : <span />}
+            <Button
+              variant="link"
+              size="xs"
+              onClick={() => setHiddenSurfaces([])}
+              className="normal-case text-muted-foreground hover:text-foreground"
+            >
+              {t('contextRail.configure.showAll')}
+            </Button>
+          </div>
+        ) : null}
+      </DialogContent>
+    </Dialog>
+  );
+};