fix(ui): align context surface icons

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

@@ -1,6 +1,7 @@
 import React from 'react';
 
 import { FileTypeIcon } from '@/components/icons/FileTypeIcon';
+import { DiffViewIcon } from '@/components/icons/DiffIcon';
 import { Button } from '@/components/ui/button';
 import { SortableTabsStrip } from '@/components/ui/sortable-tabs-strip';
 import { DiffView } from '@/components/views/DiffView';
@@ -246,7 +247,7 @@ const getTabIcon = (tab: { mode: ContextPanelMode; targetPath: string | null }):
   }
 
   if (tab.mode === 'diff') {
-    return <Icon name="arrow-left-right" className="h-3.5 w-3.5" />;
+    return <DiffViewIcon className="h-3.5 w-3.5" />;
   }
 
   if (tab.mode === 'walkthrough') {
@@ -258,7 +259,7 @@ const getTabIcon = (tab: { mode: ContextPanelMode; targetPath: string | null }):
   }
 
   if (tab.mode === 'pr') {
-    return <Icon name="git-pull-request" className="h-3.5 w-3.5" />;
+    return <Icon name="github" className="h-3.5 w-3.5" />;
   }
 
   if (tab.mode === 'notes') {

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

@@ -17,6 +17,7 @@ import {
 import { CSS } from '@dnd-kit/utilities';
 
 import { Icon } from '@/components/icon/Icon';
+import { DiffViewIcon } from '@/components/icons/DiffIcon';
 import { Tooltip, TooltipContent, TooltipTrigger } from '@/components/ui/tooltip';
 import { useEffectiveDirectory } from '@/hooks/useEffectiveDirectory';
 import { useDeviceInfo } from '@/lib/device';
@@ -80,7 +81,11 @@ const ContextPanelRailItem: React.FC<RailItemProps> = ({
                 : 'text-muted-foreground hover:text-foreground',
             )}
           >
-            <Icon name={surface.icon} className="h-[18px] w-[18px]" />
+            {surface.id === 'diff' ? (
+              <DiffViewIcon />
+            ) : (
+              <Icon name={surface.icon} className="h-[18px] w-[18px]" />
+            )}
             {showActivityDot ? (
               <span
                 aria-hidden="true"